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  • 1. Baev, A.
    et al.
    Gelmukhanov, Faris
    KTH, Superseded Departments, Chemistry.
    Kimberg, Viktor
    KTH, Superseded Departments, Biotechnology.
    Ågren, Hans
    KTH, Superseded Departments, Biotechnology.
    Nonlinear propagation of strong multi-mode fields2003In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 36, p. 3761-3774Article in journal (Refereed)
    Abstract [en]

    We develop a strict theory of nonlinear propagation of few interacting stronglight beams. The key idea of our approach is a self-consistent solution ofthe nonlinear wave equation and the density matrix equations of the materialbeyond the rotatory wave approximation. We assume a Fourier expansion ofthe density matrixwhich goes beyond the conventionalTaylor expansions of thepolarization over the field amplitudeswhich is inadequate for the field strengthsthat we are interested in. Two qualitatively different situations are considered,with and without phase matching. Unlike in our previous paper (Baev et al2003 J. Opt. Soc. Am. B at press) devoted to the three-photon (TP) absorptioninduced upconverted lasing, we obtain here a strict solution for the nonlinearinteraction between different light beams. The general theory is applied to anumerical study of the role of saturation in TP photoabsorption by an organicchromophore in solution.

  • 2. Baev, A.
    et al.
    Kimberg, Viktor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Polyutov, Sergey
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Gelmukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Bi-directional description of amplified spontaneous emission induced by three-photon absorption2005In: Journal of the Optical Society of America. B, Optical physics, ISSN 0740-3224, E-ISSN 1520-8540, Vol. 22, no 2, p. 385-393Article in journal (Refereed)
    Abstract [en]

     A semiclassical dynamic theory of the nonlinear propagation of a few interacting intense light pulses is applied to study the nonlinear counterpropagation of amplified spontaneous emission (ASE) induced by three-photon absorption of short intense laser pulses in a chromophore solution. Several important results from the modeling are reached for the ASE process developing in the regime of strong saturation. Accounting for ASE in both forward and backward directions with respect to the pump pulse results in a smaller efficiency of nonlinear conversion for the forward ASE compared with the case in which forward emission is considered alone, something that results from the partial repump of the absorbed energy to the backward ASE component; the overall efficiency is nevertheless higher than for the forward emission considered alone. The efficiency of nonlinear conversion of the pump energy to the counterpropagating ASE pulses is strongly dependent on the concentration of active molecules so that a particular combination of concentration versus cell length optimizes the conversion coefficient. Under certain specified conditions, the ASE effect is found to be oscillatory; the origin of oscillations is dynamical competition between stimulated emission and off-resonant absorption. This result can be considered one of the possible explanations of the temporal fluctuations of the forward ASE pulse [Nature 415, 767 (2002)].

  • 3.
    C. Couto, Rafael
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Vaz da Cruz, Vinícius
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ertan, Emelie
    Eckert, Sebastian
    Fondell, Mattis
    Dantz, Marcus
    Kennedy, Brian
    Schmitt, Thorsten
    Pietzsch, Annette
    F. Guimarães, Freddy
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Gel’mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Odelius, Michael
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Föhlisch, Alexander
    Selective gating to vibrational modes through resonant X-ray scattering2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, p. 14165-1-14165-7Article in journal (Refereed)
    Abstract [en]

    The dynamics of fragmentation and vibration of molecular systems with a large number of coupled degrees of freedom are key aspects for understanding chemical reactivity and properties. Here we present a resonant inelastic X-ray scattering (RIXS) study to show how it is possible to break down such a complex multidimensional problem into elementary components. Local multimode nuclear wave packets created by X-ray excitation to different core-excited potential energy surfaces (PESs) will act as spatial gates to selectively probe the particular ground-state vibrational modes and, hence, the PES along these modes. We demonstrate this principle by combining ultra-high resolution RIXS measurements for gas-phase water with state-of-the-art simulations.

  • 4.
    Couto, Rafael C.
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Universidade Federal Goiás, Brasilia.
    Guarise, Marco
    Nicolaou, Alessandro
    Jaouen, Nicolas
    Chiuzbaian, Gheorghe S.
    Luening, Jan
    Ekholm, Victor
    Rubensson, Jan-Erik
    Sathe, Conny
    Hennies, Franz
    Guimaraes, Freddy F.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Gel'mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Journel, Loic
    Simon, Marc
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Coupled electron-nuclear dynamics in resonant 1 sigma -> 2 pi x-ray Raman scattering of CO molecules2016In: Physical Review A, ISSN 2469-9926, Vol. 93, no 3, article id 032510Article in journal (Refereed)
    Abstract [en]

    We present a detailed experimental-theoretical analysis of O K-edge resonant 1 sigma-2 pi inelastic x-ray scattering (RIXS) from carbon monoxide with unprecedented energy resolution. We employ high-level ab initio calculations to compute the potential energy curves of the states involved in the RIXS process and simulate the measured RIXS spectra using the wave-packet-propagation formalism, including Coulomb coupling in the final-state manifold. The theoretical analysis allows us to explain all the key features of the experimental spectra, including some that were not seen before. First, we clearly show the interference effect between different RIXS channels corresponding to the transition via orthogonal (1)Pi(x) and (1)Pi(y) core-excited states of CO. Second, the RIXS region of 13 eV energy loss presents a triple structure, revealed only by the high-resolution measurement. In previous studies, this region was attributed solely to a valence state. Here we show a strong Coulomb mixing of the Rydberg and valence final states, which opens the forbidden RIXS channels to the "dark" final Rydberg states and drastically changes the RIXS profile. Third, using a combination of high-resolution experiment and high-level theory, we improve the vertical bar 4 sigma(-1)2 pi(1)> final-state potential-energy curve by fitting its bottom part with the experiment. Also, the coupling constants between Rydberg and valence states were refined via comparison with the experiment. Our results illustrate the large potential of the RIXS technique for advanced studies of highly excited states of neutral molecules.

  • 5.
    Couto, Rafael C.
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Univ Fed Goias, Brazil.
    Guarise, Marco
    Nicolaou, Alessandro
    Jaouen, Nicolas
    Chiuzbaian, Gheorghe S.
    Luening, Jan
    Ekholm, Victor
    Rubensson, Jan-Erik
    Sathe, Conny
    Hennies, Franz
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Guimaraes, Freddy F.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Gel'mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Journel, Loic
    Simon, Marc
    Anomalously strong two-electron one-photon X-ray decay transitions in CO caused by avoided crossing2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 20947Article in journal (Refereed)
    Abstract [en]

    The unique opportunity to study and control electron-nuclear quantum dynamics in coupled potentials offered by the resonant inelastic X-ray scattering (RIXS) technique is utilized to unravel an anomalously strong two-electron one-photon transition from core-excited to Rydberg final states in the CO molecule. High-resolution RIXS measurements of CO in the energy region of 12-14 eV are presented and analyzed by means of quantum simulations using the wave packet propagation formalism and ab initio calculations of potential energy curves and transition dipole moments. The very good overall agreement between the experimental results and the theoretical predictions allows an in-depth interpretation of the salient spectral features in terms of Coulomb mixing of "dark" with "bright" final states leading to an effective two-electron one-photon transition. The present work illustrates that the improved spectral resolution of RIXS spectra achievable today may call for more advanced theories than what has been used in the past.

  • 6.
    da Cruz, Vinicius Vaz
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Royal Inst Technol, Theoret Chem & Biol, S-10691 Stockholm, Sweden..
    Ertan, Emelie
    Stockholm Univ, AlbaNova Univ Ctr, Dept Phys, S-10691 Stockholm, Sweden..
    Ignatova, Nina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Inst Nanotechnol Spect & Quantum Chem, Krasnoyarsk 660041, Russia..
    Couto, Rafael C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Polyutov, Sergey
    Siberian Fed Univ, Inst Nanotechnol Spect & Quantum Chem, Krasnoyarsk 660041, Russia..
    Odelius, Michael
    Stockholm Univ, AlbaNova Univ Ctr, Dept Phys, S-10691 Stockholm, Sweden..
    Kimberg, Victor
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Inst Nanotechnol Spect & Quantum Chem, Krasnoyarsk 660041, Russia..
    Gel'mukhanov, Faris
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Royal Inst Technol, Theoret Chem & Biol, S-10691 Stockholm, Sweden.
    Anomalous polarization dependence in vibrationally resolved resonant inelastic x-ray scattering of H2O2018In: Physical Review A: covering atomic, molecular, and optical physics and quantum information, ISSN 2469-9926, E-ISSN 2469-9934, Vol. 98, no 1, article id 012507Article in journal (Refereed)
    Abstract [en]

    It is well established that different electronic channels, in resonant inelastic x-ray scattering (RIXS), display different polarization dependences due to different orientations of their corresponding transition dipole moments in the molecular frame. However, this effect does not influence the vibrational progression in the Franck-Condon approximation. We have found that the transition dipole moments of core excitation and deexcitation experience ultrafast rotation during dissociation in the intermediate core-excited state. This rotation makes the vibrational progression in RIXS sensitive to the polarization of the x-ray photons. We study the water molecule, in which the effect is expressed in RIXS through the dissociative core-excited state where the vibrational scattering anisotropy is accompanied also by violation of parity selection rules for the vibrations.

  • 7.
    da Cruz, Vinicius Vaz
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Gel'mukhanov, Faris
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Lab Nonlinear Opt & Spect, Krasnoyarsk 660041, Russia.
    Eckert, Sebastian
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Iannuzzi, Marcella
    Univ Zurich, Phys Chem Inst, CH-8057 Zurich, Switzerland..
    Ertan, Emelie
    Stockholm Univ, Dept Phys, AlbaNova Univ Ctr, S-10691 Stockholm, Sweden..
    Pietzsch, Annette
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Couto, Rafael C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Niskanen, Johannes
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany.;Univ Turku, Dept Phys & Astron, FI-20014 Turunyliopisto, Finland..
    Fondell, Mattis
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Dantz, Marcus
    Paul Scherrer Inst, Photon Sci Div, CH-5232 Villigen, Switzerland..
    Schmitt, Thorsten
    Paul Scherrer Inst, Photon Sci Div, CH-5232 Villigen, Switzerland..
    Lu, Xingye
    Paul Scherrer Inst, Photon Sci Div, CH-5232 Villigen, Switzerland..
    McNally, Daniel
    Paul Scherrer Inst, Photon Sci Div, CH-5232 Villigen, Switzerland..
    Jay, Raphael M.
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Kimberg, Victor
    Foehlisch, Alexander
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany.;Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Odelius, Michael
    Stockholm Univ, Dept Phys, AlbaNova Univ Ctr, S-10691 Stockholm, Sweden..
    Probing hydrogen bond strength in liquid water by resonant inelastic X-ray scattering2019In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, article id 1013Article in journal (Refereed)
    Abstract [en]

    Local probes of the electronic ground state are essential for understanding hydrogen bonding in aqueous environments. When tuned to the dissociative core-excited state at the O1s pre-edge of water, resonant inelastic X-ray scattering back to the electronic ground state exhibits a long vibrational progression due to ultrafast nuclear dynamics. We show how the coherent evolution of the OH bonds around the core-excited oxygen provides access to high vibrational levels in liquid water. The OH bonds stretch into the long-range part of the potential energy curve, which makes the X-ray probe more sensitive than infra-red spectroscopy to the local environment. We exploit this property to effectively probe hydrogen bond strength via the distribution of intramolecular OH potentials derived from measurements. In contrast, the dynamical splitting in the spectral feature of the lowest valence-excited state arises from the short-range part of the OH potential curve and is rather insensitive to hydrogen bonding.

  • 8.
    da Cruz, Vinicius Vaz
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Ignatova, Nina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Krasnoyarsk 660041, Russia.;Fed Res Ctr KSC SB RAS, Kirensky Inst Phys, Krasnoyarsk 660036, Russia..
    Couto, Rafael C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Fedotov, Daniil A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Krasnoyarsk 660041, Russia..
    Rehn, Dirk R.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Savchenko, Viktoriia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Krasnoyarsk 660041, Russia.;Fed Res Ctr KSC SB RAS, Kirensky Inst Phys, Krasnoyarsk 660036, Russia..
    Norman, Patrick
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Polyutov, Sergey
    Siberian Fed Univ, Krasnoyarsk 660041, Russia.;Fed Res Ctr KSC SB RAS, Kirensky Inst Phys, Krasnoyarsk 660036, Russia..
    Niskanen, Johannes
    Univ Turku, Dept Phys & Astron, FI-20014 Turun, Finland.;Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Eckert, Sebastian
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Jay, Raphael M.
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Fondell, Mattis
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Schmitt, Thorsten
    Paul Scherrer Inst, Photon Sci Div, CH-5232 Villigen, Switzerland..
    Pietzsch, Annette
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Foehlisch, Alexander
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany.;Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Gel'mukhanov, Faris
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Krasnoyarsk 660041, Russia.;Fed Res Ctr KSC SB RAS, Kirensky Inst Phys, Krasnoyarsk 660036, Russia..
    Odelius, Michael
    Stockholm Univ, AlbaNova Univ Ctr, Dept Phys, S-10691 Stockholm, Sweden..
    Kimberg, Victor
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Krasnoyarsk 660041, Russia.;Fed Res Ctr KSC SB RAS, Kirensky Inst Phys, Krasnoyarsk 660036, Russia..
    Nuclear dynamics in resonant inelastic X-ray scattering and X-ray absorption of methanol2019In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 150, no 23, article id 234301Article in journal (Refereed)
    Abstract [en]

    We report on a combined theoretical and experimental study of core-excitation spectra of gas and liquid phase methanol as obtained with the use of X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS). The electronic transitions are studied with computational methods that include strict and extended second-order algebraic diagrammatic construction [ADC(2) and ADC(2)-x], restricted active space second-order perturbation theory, and time-dependent density functional theory-providing a complete assignment of the near oxygen K-edge XAS. We show that multimode nuclear dynamics is of crucial importance for explaining the available experimental XAS and RIXS spectra. The multimode nuclear motion was considered in a recently developed "mixed representation" where dissociative states and highly excited vibrational modes are accurately treated with a time-dependent wave packet technique, while the remaining active vibrational modes are described using Franck-Condon amplitudes. Particular attention is paid to the polarization dependence of RIXS and the effects of the isotopic substitution on the RIXS profile in the case of dissociative core-excited states. Our approach predicts the splitting of the 2a RIXS peak to be due to an interplay between molecular and pseudo-atomic features arising in the course of transitions between dissociative core- and valence-excited states. The dynamical nature of the splitting of the 2a peak in RIXS of liquid methanol near pre-edge core excitation is shown. The theoretical results are in good agreement with our liquid phase measurements and gas phase experimental data available from the literature.

  • 9. Ertan, Emelie
    et al.
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Fed Univ, Russia.
    Gel'mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Fed Univ, Russia.
    Hennies, Franz
    Rubensson, Jan-Erik
    Schmitt, Thorsten
    Strocov, Vladimir N.
    Zhou, Kejin
    Iannuzzi, Marcella
    Foehlisch, Alexander
    Odelius, Michael
    Pietzsch, Annette
    Theoretical simulations of oxygen K-edge resonant inelastic x-ray scattering of kaolinite2017In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 95, no 14, article id 144301Article in journal (Refereed)
    Abstract [en]

    Near-edge x-ray absorption fine structure (NEXAFS) and resonant inelastic x-ray scattering (RIXS) measurements at the oxygen K edge were combined with theoretical spectrum simulations, based on periodic density functional theory and nuclear quantum dynamics, to investigate the electronic structure and chemical bonding in kaolinite Al2Si2O5(OH)(4). We simulated NEXAFS spectra of all crystallographically inequivalent oxygen atoms in the crystal and RIXS spectra of the hydroxyl groups. Detailed insight into the ground-state potential energy surface of the electronic states involved in the RIXS process were accessed by analyzing the vibrational excitations, induced by the core excitation, in quasielastic scattering back to the electronic ground state. In particular, we find that the NEXAFS pre-edge is dominated by features related to OH groups within the silica and alumina sheets, and that the vibrational progression in RIXS can be used to selectively probe vibrational modes of this subclass of OH groups. The signal is dominated by the OH stretching mode, but also other lower vibrational degrees of freedom, mainly hindered rotational modes, contribute to the RIXS signal.

  • 10.
    Ertan, Emelie
    et al.
    Stockholm university.
    Savchenko, Viktoriia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Federal University.
    Ignatova, Nina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Federal University.
    da Cruz, Vinicius Vaz
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Couto, Rafael C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Eckert, Sebastian
    Institut für Physik und Astronomie, Universität Potsdam.
    Fondell, Mattis
    Dantz, Marcus
    Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut.
    Kennedy, Brian
    Institute for Methods and Instrumentation in Synchrotron Radiation Research G- ISRR, Helmholtz-Zentrum Berlin für Materialien und Energie.
    Schmitt, Thorsten
    Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut.
    Pietzsch, Annette
    Institute for Methods and Instrumentation in Synchrotron Radiation Research G- ISRR, Helmholtz-Zentrum Berlin für Materialien und Energie.
    Föhlisch, Alexander
    Institut für Physik und Astronomie, Universität Potsdam.
    Gel'mukhanov, Faris
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Odelius, Michael
    Stockholm university.
    Kimberg, Victor
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Ultrafast dissociation features in RIXS spectra of the water molecule2018In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084Article in journal (Refereed)
    Abstract [en]

    In this combined theoretical and experimental study we report on an analysis of the resonant inelastic X-ray scattering spectra (RIXS) of gas phase water via the lowest dissociative core-excited state |1sO-14a11〉. We focus on the spectral feature near the dissociation limit of the electronic ground state. We show that the narrow atomic-like peak consists of the overlapping contribution from the RIXS channels back to the ground state and to the first valence excited state |1b1-14a11〉 of the molecule. The spectral feature has signatures of ultrafast dissociation (UFD) in the core-excited state, as we show by means of ab initio calculations and time-dependent nuclear wave packet simulations. We show that the electronically elastic RIXS channel gives substantial contribution to the atomic-like resonance due to the strong bond length dependence of the magnitude and orientation of the transition dipole moment. By studying the RIXS for an excitation energy scan over the core-excited state resonance, we can understand and single out the molecular and atomic-like contributions in the decay to the lowest valence-excited state. Our study is complemented by a theoretical discussion of RIXS in the case of the isotope substituted water (HDO and D2O) where the nuclear dynamics is significantly affected by the heavier fragments' mass.

  • 11. Feifel, R.
    et al.
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Baev, Alexander
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Gel'mukhanov, Faris
    KTH, Superseded Departments, Biotechnology.
    Ågren, Hans
    KTH, Superseded Departments, Biotechnology.
    Miron, C.
    Ohrwall, G.
    Piancastelli, M. N.
    Sorensen, S. L.
    Karlsson, L.
    Svensson, S.
    Profile of resonant photoelectron spectra versus the spectral function width and photon frequency detuning2004In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 70, no 3Article in journal (Refereed)
    Abstract [en]

    The outermost, singly ionized valence state of N-2, the X (2)Sigma(g)(+) state, is investigated in detail as a function of the photon frequency bandwidth for core excitation to the N 1s-->pi(*) resonance, where the photon frequency is tuned in between the first two vibrational levels of this bound intermediate electronic state. We find a strong, nontrivial dependence of the resulting resonant photoemission spectral profile on the monochromator function width and the frequency of its peak position. For narrow bandwidth excitation we observe a well resolved vibrational fine structure in the final electron spectrum, which for somewhat broader bandwidths gets smeared out into a continuous structure. For even broader monochromator bandwidths, it converts again into a well resolved vibrational progression. In addition, spectral features appearing below the adiabatic transition energy of the ground state of N-2(+) are observed for broadband excitation. A model taking into account the interplay of the partial scattering cross section with the spectral function is presented and applied to the X (2)Sigma(g)(+) final state of N-2(+).

  • 12.
    Gel'mukhanov, Faris
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Liu, X. J.
    Prumper, G.
    Tanaka, T.
    Hoshino, M.
    Tanaka, H.
    Ueda, K.
    Young's double-slit experiment using two-center core-level photoemission: Photoelectron recoil effects2007In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 156, p. 265-269Article in journal (Refereed)
    Abstract [en]

    Core-level photoemission from N-2 can be considered an analogue of Young's double-slit experiment (YDSE) in which the double-slit is replaced by a pair of N 1s orbitals. The measured ratio between the 1 sigma(g) and 1 sigma(u) photoionization cross-sections oscillates as a function of photoelectron momentum, due to two-center YDSE interference, exhibiting a remarkable dependence on the vibrational sub-levels of the core ionized state. We theoretically demonstrate that the recoil of the photoelectron given to the ionized N atom strongly influences this interference pattern. The reason for this is that the momentum transfer affects the phases of the photoionization amplitudes.

  • 13.
    Gelmukhanov, Faris
    et al.
    KTH, Superseded Departments, Biotechnology.
    Kimberg, Victor
    KTH, Superseded Departments, Biotechnology.
    Ågren, Hans
    KTH, Superseded Departments, Biotechnology.
    X-ray Doppler spectroscopy of ultrafast fragmentation2004In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Chem. Phys., Vol. 299, p. 253-258Article in journal (Refereed)
    Abstract [en]

    Doppler effects are now commonly observed for Auger resonances of dissociating atoms in randomly oriented molecules. The physics behind the, yet not observed, Doppler effect for fixed-in-space molecules is different in that there will appear extra Doppler resonances resulting from the diffractional scattering of the Auger electrons by the surrounding atoms. It is argued that as these resonances will show maxima in the bond directions their measurement by current energy and angular resolved electron-ion coincidence experiments will provide structural probing. It is also shown that the electronic Doppler effect caused by nuclear vibrations can be observed also for bound nuclear states making use of electron-ion coincidence measurements. Optimal conditions for such measurements prevail when the scattering duration is comparable with a vibrational period.

  • 14.
    Gelmukhanov, Faris
    et al.
    KTH, Superseded Departments, Biotechnology.
    Kimberg, Viktor
    KTH, Superseded Departments, Biotechnology.
    Ågren, Hans
    KTH, Superseded Departments, Biotechnology.
    Structure determination through measurements of Doppler-split Augerresonances in fixed-in-space molecules2004In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 69, no 2, p. 020501(R)-Article in journal (Refereed)
    Abstract [en]

    Auger resonances of dissociating atoms in randomly oriented molecules experience large electronic Dopplershifts. We predict that when fixed-in-space molecules are considered there will appear extra Doppler resonancesresulting from the diffractional scattering of the Auger electrons by the surrounding atoms. Theseresonances show sharp maxima in bond directions, something that makes them very promising as probes forlocal molecular structure using current energy- and angular-resolved electron-ion coincidence experiments.

  • 15.
    Guimaraes, Freddy Fernandes
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Felicissimo, Viviane C.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Gelmukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Cesar, A.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Infrared–x-ray pump-probe spectroscopy of the NO molecule2005In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 72, no 1, article id 012714Article in journal (Refereed)
    Abstract [en]

    Two color infrared-x-ray pump-probe spectroscopy of the NO molecule is studied theoretically and numerically in order to obtain a deeper insight of the underlying physics and of the potential of this suggested technology. From the theoretical investigation a number of conclusions could be drawn: It is found that the phase of the infrared field strongly influences the trajectory of the nuclear wave packet, and hence, the x-ray spectrum. The trajectory experiences fast oscillations with the vibrational frequency with a modulation due to the anharmonicity of the potential. The dependences of the x-ray spectra on the delay time, the duration, and the shape of the pulses are studied in detail. It is shown that the x-ray spectrum keep memory about the infrared phase after the pump field left the system. This memory effect is sensitive to the time of switching-off the pump field and the Rabi frequency. The phase effect takes maximum value when the duration of the x-ray pulse is one-fourth of the infrared field period, and can be enhanced by a proper control of the duration and intensity of the pump pulse. The manifestation of the phase is different for oriented and disordered molecules and depends strongly on the intensity of the pump radiation.

  • 16.
    Guimaraes, Freddy Fernandes
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Kimberg, Victor
    KTH, School of Biotechnology (BIO).
    Felicissimo, Viviane C.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Gel'mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Cesar, A.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Phase sensitive x-ray absorption driven by strong infrared fields2005In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 71, no 4, article id 043407Article in journal (Refereed)
    Abstract [en]

    In this paper it is demonstrated that electron vibrational absorption of molecules driven by strong IR field provides rich physical interpretations of dynamical processes on a short time scale. The phase of an infrared field influences strongly the trajectory of the nuclear wave packet and the probing spectrum. It is shown that the probe spectrum keeps memory of the infrared phase even after that the pump field left the system. The phase effect takes maximum value when the duration of the probe pulse is of the order of the infrared field period, and can be enhanced by a proper control of the duration and intensity of the pump pulse. The phase effect is different for oriented and disordered molecules and depends strongly on the intensity of pump radiation. It can be an effective tool to study charge transfer processes like proton transfer in hydrogen bonded networks.

  • 17.
    Guimaraes, Freddy
    et al.
    KTH, Superseded Departments, Biotechnology.
    Kimberg, Vikctor
    KTH, Superseded Departments, Biotechnology.
    Gel'mukhanov, Faris
    KTH, Superseded Departments, Biotechnology.
    Ågren, Hans
    KTH, Superseded Departments, Biotechnology.
    Two-color phase-sensitive x-ray pump-probe spectroscopy2004In: Phys. Rev. A, ISSN 1050-2947, Vol. 70, p. 062504-Article in journal (Refereed)
    Abstract [en]

    X-ray pump-probe spectroscopy is studied theoretically. It is shown that two-color-optical+x-ray-excitation with constant phase of the pump radiation exhibits strong interference between the one- and two-photon excitation channels. This effect is found to be large for both long and short pump pulses, while the interference vanishes for x-ray pulses longer than one cycle of the pump field. It is predicted that the spectral shape of x-ray absorption is strongly influenced by the absolute phase of the pump light. A strong sensitivity of the x-ray absorption and/or photoionization profile to the phase and detuning of the pump field is predicted, as well as to the duration of the x-ray pulse. Our simulations display oscillations of x-ray absorption as a function of the delay time. This effect allows the synchronization of the x-ray pulse relative to the "comb" of the pump radiation. The interference pattern copies the temporal and space distribution of the pump field. We pay special attention to the role of molecular orientation for the interference effect.

  • 18. Kikas, A.
    et al.
    Kaambre, T.
    Saar, A.
    Kooser, K.
    Nommiste, E.
    Martinson, I.
    Kimberg, Victor
    KTH, Superseded Departments, Chemistry.
    Polyutov, Sergey
    KTH, Superseded Departments, Chemistry.
    Gel'mukhanov, Faris
    KTH, Superseded Departments, Biotechnology.
    Resonant inelastic x-ray scattering at the F 1s photoabsorption edge in LiF: Interplay of excitonic and conduction states, and Stokes' doubling2004In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 70, no 8Article in journal (Refereed)
    Abstract [en]

    The excitation-decay processes at the F 1s photoabsorption edge in LiF crystal are studied using resonant inelastic x-ray scattering spectroscopy. The Raman-type linear dispersion and the narrowing of the x-ray fluorescence peak are observed at resonant excitation. A theoretical model based on the Kramers-Heisenberg formula describes well the main features in fluorescence spectra and allows one to separate the contributions of the exciton and the conduction states in the scattering spectra. At the same time, the role of the shape of the spectral distribution within the incident radiation is emphasized as being critically sensitive to the number, kind, and onset of the spectral features which finally appear in the scattering spectra at a particular incident photon energy, particularly in the subthreshold excitation region.

  • 19.
    Kimberg, Victor
    KTH, School of Biotechnology (BIO).
    Pulse Propagation in Nonlinear Media and Photonic Crystals2006Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The present thesis is devoted to theoretical studies of pulse propagation of light through linear and nonlinear media, and of light-induced nuclear dynamics.

    The first part of the thesis addresses propagation of light pulses in linear periodical media - photonic crystals. The main accent was put on studies of the angular properties of two qualitatively different types of photonic crystals: holographic photonic crystals, and impurity band based photonic crystals. The anisotropy of band structure, group velocity and pulse delay with respect to the light polarization are analyzed.

    In the second part of the thesis a strict theory of nonlinear propagation of a few strong interacting light beams is presented. The key idea of this approach is a self-consistent solution of the nonlinear wave equation and the density matrix equations of the material. This technique is applied to studies of dynamics of cavityless lasing generated by ultra-fast multi-photon excitation. It is shown that interaction of co- and counter-propagating pulses of amplified spontaneous emission (ASE) affects the dynamics and efficiency of nonlinear conversion. Our dynamical theory allows to explain the asymmetric spectral properties of the forward and backward ASE pulses, which were observed in recent experiment with different dye molecules. It is shown that the ASE spectral profile changes drastically when the pump intensity approaches the threshold level. The effect of the temporal self-pulsation of ASE is studied in detail.

    The third part of the thesis is devoted to light-induced nuclear dynamics. Time- and frequency-resolved X-ray spectroscopy of molecules driven by strong and coherent infrared (IR) pulses shows that the phase of the IR field strongly influences the trajectory of the nuclear wave packet, and hence, the X-ray spectrum. Such a dependence arises due to the interference of one (X-ray) and two-photon (X-ray + IR) excitation channels. The phase of the light influences the dynamics also when the Rabi frequency approaches the vibrational frequency, breaking down the rotating-wave approximation. The probe X-ray spectra are also sensitive to the delay time, the duration, and the shape of the pulses. The evolution of the nuclear wave packets in the dissociative core-excited state affects the dynamics of resonant Auger scattering from fixed-in-space molecules. One of the important dynamical effects is the atomic-like resonance which experiences electronic Doppler shift. We predict that the scattering of the Auger electrons by nearby atoms leads to new Doppler shifted resonances. These extra resonances show sharp maxima in the bond directions, which makes them very promising as probes for local molecular structure using energy and angular resolved electron-ion coincidence techniques. Our theory provides prediction of several new effects, but also results that are in good agreement with the available experimental data.

  • 20.
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Pulse propagation in photonic crystals and nonlinear media2005Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The present thesis is devoted to theoretical studies of light pulse propagation through different linear and nonlinear media. One dimensional holographic photonic crystals and one dimensional impurity band based photonic crystals are investigated as linear media. The effects of angular dependence of the band structures and pulse delay with respect to the light polarization are analyzed. A strict theory of nonlinear propagation of a few strong interacting light beams is presented and applied in the field of nonlinear optics. The key idea of this approach is a self-consistent solution of the nonlinear wave equation and the density matrix equations of the material beyond the so-called rotating wave approximation. The results of numerical studies led to a successful interpretation of recent experimental data [Nature, 415:767, 2002]. A theoretical study of the NO molecule by means of two-color infrared -- X-ray pump probe spectroscopy is presented. It was found that the phase of the infrared field strongly influences the trajectory of the nuclear wave packet, and hence, the X-ray spectrum. The dependence of the X-ray spectra on the delay time, the duration and the shape of the pulses are studied.

  • 21.
    Kimberg, Victor
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Gelmukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Angular anisotropy of the delay time of short pulses in impurity band based photonic crystals2005In: Journal of Optics. A, Pure and applied optics, ISSN 1464-4258, E-ISSN 1741-3567, Vol. 7, no 3, p. 118-122Article in journal (Refereed)
    Abstract [en]

    We investigate the transmission of short pulses through one-dimensional impurity band based photonic crystals. We found a strong dependence of the delay time on the angle of incidence. The delay time is larger for larger incident angles for the transverse electrical mode, while the delay time of the transverse magnetic mode has a qualitatively different angular dependence, especially in the region below the Brewster angle. The strong anisotropy of the delay time is traced to the anisotropy of the group velocity which is directly related to the angular dependence of the impurity band structure.

  • 22.
    Kimberg, Victor
    et al.
    KTH, Superseded Departments, Biotechnology.
    Gelmukhanov, Faris
    KTH, Superseded Departments, Biotechnology.
    Ågren, Hans
    KTH, Superseded Departments, Biotechnology.
    Pent, E.
    Plekhanov, A.
    Kuchin, I.
    Rodionov, M.
    Shelkovnikov, V.
    Angular properties of band structures in one-dimensional holographic photonic crystals2004In: Journal of Optics. A, Pure and applied optics, ISSN 1464-4258, E-ISSN 1741-3567, Vol. 6, no 10, p. 991-996Article in journal (Refereed)
    Abstract [en]

    One-dimensional photonic crystals with continuous distribution of the dielectric constant were fabricated by the use of photopolymer materials and laser holography. The angular dependence of light propagation through the system was studied experimentally and theoretically. It is shown that the Brewster angles for different bands are different, in contrast to the conventional two-layer Bragg reflector with a step-like distribution of the dielectric constant. Comparison of the theory with experimental data allowed us to define the parameters of the hologram-the dielectric contrast and the shrinkage of the structure.

  • 23.
    Kimberg, Victor
    et al.
    KTH, School of Biotechnology (BIO).
    Guimaraes, Freddy Fernandes
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Felicissimo, Viviane C.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Gel'mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Phase-sensitive wave-packet dynamics caused by a breakdown of the rotating-wave approximation2006In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 73, no 2, article id 023409Article in journal (Refereed)
    Abstract [en]

    The water dimer driven by strong infrared field is studied in the two-vibrational mode approximation. A pump pulse excites the OH vibrational modes and creates a coherent superposition of vibrational states of the low-frequency OO mode. The solution of the Schrodinger equation in the adiabatic approximation shows a strong sensitivity of the OO vibrational wave-packet dynamics to the absolute phase of the pump field. This effect appears due to a break down of the rotating-wave approximation when the Rabi frequency of the OH vibrational transition approaches the frequency of the OH mode. The violation of the rotating wave approximation modifies considerably the interaction of the probe radiation with the laser-driven molecule.

  • 24.
    Kimberg, Victor
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Polyutov, Sergey
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Gel'mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Baev, Alexander
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Zheng, Q.D.
    Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo.
    He, G. S.
    Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo.
    Dynamics of cavityless lasing generated by ultrafast multiphoton excitation2006In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 74, no 3, article id 033814Article in journal (Refereed)
    Abstract [en]

    A dynamical theory is developed with the purpose of explaining recent experimental results on multiphoton-excited amplified stimulated emission (ASE). Several conspicuous features of this experiment are analyzed, like the threshold dependence of the spectral profile on the pump intensity, and spectral shifts of the ASE pulses co- and counterpropagating relative to the pump pulse. Two models are proposed and evaluated, one based on the isolated molecule and another which involves solvent interaction. The spectral shift between the forward and backward ASE pulses arises in the first model through the competition between the ASE transitions from the pumped vibrational levels and from the bottom of the excited-state well, while in the solvent-related model the dynamical solute-solvent interaction leads to a relaxed excited state, producing an additional ASE channel. In the latter model the additional redshifted ASE channel makes the dynamics of ASE essentially different from that in the molecular model because the formation of the relaxed state takes a longer time. The variation of the pump intensity influences strongly the relative intensities of the different ASE channels and, hence, the spectral shape of ASE in both models. The regime of ASE changes character when the pump intensity crosses a threshold value. Such a phase transition occurs when the ASE rate approaches the rate of vibrational relaxation or the rate of solute-solvent relaxation in the first excited state.

  • 25.
    Kimberg, Victor
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Max Planck Institute for the Physics of Complex Systems, Germany.
    Rohringer, N.
    Stochastic stimulated electronic x-ray Raman spectroscopy2016In: Structural Dynamics, ISSN 2329-7778, Vol. 3, no 3, article id 34101Article in journal (Refereed)
    Abstract [en]

    Resonant inelastic x-ray scattering (RIXS) is a well-established tool for studying electronic, nuclear, and collective dynamics of excited atoms, molecules, and solids. An extension of this powerful method to a time-resolved probe technique at x-ray free electron lasers (XFELs) to ultimately unravel ultrafast chemical and structural changes on a femtosecond time scale is often challenging, due to the small signal rate in conventional implementations at XFELs that rely on the usage of a monochromator setup to select a small frequency band of the broadband, spectrally incoherent XFEL radiation. Here, we suggest an alternative approach, based on stochastic spectroscopy, which uses the full bandwidth of the incoming XFEL pulses. Our proposed method is relying on stimulated resonant inelastic x-ray scattering, where in addition to a pump pulse that resonantly excites the system a probe pulse on a specific electronic inelastic transition is provided, which serves as a seed in the stimulated scattering process. The limited spectral coherence of the XFEL radiation defines the energy resolution in this process and stimulated RIXS spectra of high resolution can be obtained by covariance analysis of the transmitted spectra. We present a detailed feasibility study and predict signal strengths for realistic XFEL parameters for the CO molecule resonantly pumped at the O1s→π* transition. Our theoretical model describes the evolution of the spectral and temporal characteristics of the transmitted x-ray radiation, by solving the equation of motion for the electronic and vibrational degrees of freedom of the system self consistently with the propagation by Maxwell equations.

  • 26.
    Liu, Jicai
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Nicolas, P
    Morin, V
    Kimberg, Victor
    KTH, School of Biotechnology (BIO).
    Kosugi, N
    Gelmukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Multimode resonant Auger scattering from the ethylene moleculeManuscript (preprint) (Other academic)
  • 27.
    Liu, Jicai
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Travnikova, O
    Lindblad, A
    Nicolas, C
    Söderström, J
    Kimberg, Victor
    KTH, School of Biotechnology (BIO).
    Ultrafast dissociation of core-excited SF6 probed by Auger-Doppler e_ect in the _eld of circularly polarized X-raysManuscript (preprint) (Other academic)
  • 28.
    Miao, Quan
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Shandong University of Science and Technology, China.
    Travnikova, Oksana
    Gel'mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Synchrotron SOLEIL, L'Orme des Merisiers, France.
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Synchrotron SOLEIL, L'Orme des Merisiers, France.
    Sun, Yu-Ping
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Shandong University of Technology, China.
    Thomas, T. Darrah
    Nicolas, Christophe
    Patanen, Minna
    Miron, Catalin
    Rotational Doppler Effect: A Probe for Molecular Orbitals Anisotropy2015In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 6, no 9, p. 1568-1572Article in journal (Refereed)
    Abstract [en]

    The vibrationally resolved X-ray photoelectron spectra of X-2 Sigma(+)(g)(3 sigma(-1)(g)) and B-2 Sigma(+)(u)(2 sigma(-1)(u)) states of N-2(+) were recorded for different photon energies and orientations of the polarization vector. Clear dependencies of the spectral line widths on the X-ray polarization as well as on the symmetry of the final electronic states are observed. Contrary to the translational Doppler, the rotational Doppler broadening is sensitive to the photoelectron emission anisotropy. On the basis of theoretical modeling, we suggest that the different rotational Doppler broadenings observed for gerade and ungerade final states result from a Young's double-slit interference phenomenon.

  • 29. Milne, Chris J.
    et al.
    Weber, Peter M.
    Kowalewski, Markus
    Marangos, Jon P.
    Johnson, Allan S.
    Forbes, Ruaridh
    Worner, Hans Jakob
    Rolles, Daniel
    Townsend, Dave
    Schalk, Oliver
    Mai, Sebastian
    Vacher, Morgane
    Miller, R. J. Dwayne
    Centurion, Martin
    Vibok, Agnes
    Domcke, Wolfgang
    Cireasa, Raluca
    Ueda, Kiyoshi
    Bencivenga, Filippo
    Neumark, Daniel M.
    Stolow, Albert
    Rudenko, Artem
    Kirrander, Adam
    Dowek, Danielle
    Martin, Fernando
    Ivanov, Misha
    Dahlstrom, Jan Marcus
    Dudovich, Nirit
    Mukamel, Shaul
    Sanchez-Gonzalez, Alvaro
    Minitti, Michael P.
    Austin, Dane R.
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Masin, Zdenek
    Attosecond processes and X-ray spectroscopy: general discussion2016In: Faraday discussions (Online), ISSN 1359-6640, E-ISSN 1364-5498, Vol. 194, p. 427-462Article in journal (Refereed)
  • 30.
    Niskanen, Johannes
    et al.
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany.;Univ Turku, Dept Phys & Astron, FI-20014 Turun, Finland..
    Fondell, Mattis
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany..
    Sahle, Christoph J.
    European Synchrotron Radiat Facil 71, F-38043 Grenoble 9, France..
    Eckert, Sebastian
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany.;Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany..
    Jay, Raphael M.
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany.;Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany..
    Gilmore, Keith
    European Synchrotron Radiat Facil 71, F-38043 Grenoble 9, France..
    Pietzsch, Annette
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany..
    Dantz, Marcus
    Paul Scherrer Inst, Photon Sci Div, Swiss Light Source, CH-5232 Villigen, Switzerland..
    Lu, Xingye
    Paul Scherrer Inst, Photon Sci Div, Swiss Light Source, CH-5232 Villigen, Switzerland..
    McNally, Daniel E.
    Paul Scherrer Inst, Photon Sci Div, Swiss Light Source, CH-5232 Villigen, Switzerland..
    Schmitt, Thorsten
    Paul Scherrer Inst, Photon Sci Div, Swiss Light Source, CH-5232 Villigen, Switzerland..
    da Cruz, Vinicius Vaz
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany..
    Kimberg, Victor
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Inst Nanotechnol Spect & Quantum Chem, Krasnoyarsk 660041, Russia..
    Gel'mukhanov, Faris
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Inst Nanotechnol Spect & Quantum Chem, Krasnoyarsk 660041, Russia..
    Foehlisch, Alexander
    Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany.;Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany..
    Compatibility of quantitative X-ray spectroscopy with continuous distribution models of water at ambient conditions2019In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 116, no 10, p. 4058-4063Article in journal (Refereed)
    Abstract [en]

    The phase diagram of water harbors controversial views on underlying structural properties of its constituting molecular moieties, its fluctuating hydrogen-bonding network, as well as pair-correlation functions. In this work, long energy-range detection of the X-ray absorption allows us to unambiguously calibrate the spectra for water gas, liquid, and ice by the experimental atomic ionization cross-section. In liquid water, we extract the mean value of 1.74 +/- 2.1% donated and accepted hydrogen bonds per molecule, pointing to a continuous-distribution model. In addition, resonant inelastic X-ray scattering with unprecedented energy resolution also supports continuous distribution of molecular neighborhoods within liquid water, as do X-ray emission spectra once the femtosecond scattering duration and proton dynamics in resonant X-ray-matter interaction are taken into account. Thus, X-ray spectra of liquid water in ambient conditions can be understood without a two-structure model, whereas the occurrence of nanoscale-length correlations within the continuous distribution remains open.

  • 31.
    Niskanen, Johannes
    et al.
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany.;Univ Turku, Dept Phys & Astron, FI-20014 Turun, Finland..
    Fondell, Mattis
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany..
    Sahle, Christoph J.
    European Synchrotron Radiat Facil, F-38043 Grenoble, France..
    Eckert, Sebastian
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany.;Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany..
    Jay, Raphael M.
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany.;Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany..
    Gilmore, Keith
    European Synchrotron Radiat Facil, F-38043 Grenoble, France..
    Pietzsch, Annette
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany..
    Dantz, Marcus
    Paul Scherrer Inst, Photon Sci Div, Swiss Light Source, CH-5232 Villigen, Switzerland..
    Lu, Xingye
    Paul Scherrer Inst, Photon Sci Div, Swiss Light Source, CH-5232 Villigen, Switzerland..
    McNally, Daniel E.
    Paul Scherrer Inst, Photon Sci Div, Swiss Light Source, CH-5232 Villigen, Switzerland..
    Schmitt, Thorsten
    Paul Scherrer Inst, Photon Sci Div, Swiss Light Source, CH-5232 Villigen, Switzerland..
    da Cruz, Vinicius Vaz
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Helmholtz Zentrum Berlin Mat & Energie GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany..
    Kimberg, Victor
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Inst Nanotechnol Spect & Quantum Chem, Krasnoyarsk 660041, Russia..
    Gel'mukhanov, Faris
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Siberian Fed Univ, Inst Nanotechnol Spect & Quantum Chem, Krasnoyarsk 660041, Russia..
    Foehlisch, Alexander
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, D-12489 Berlin, Germany.;Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany..
    REPLY TO PETTERSSON ET AL.: Why X-ray spectral features are compatible to continuous distribution models in ambient water2019In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 116, no 35, p. 17158-17159Article in journal (Refereed)
  • 32.
    Polyutov, Sergey
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Baev, A.
    Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo.
    Gel'mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Self-sustained pulsation of amplified spontaneous emission of molecules in solution2006In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 39, no 2, p. 215-227Article in journal (Refereed)
    Abstract [en]

    Temporal oscillations of amplified spontaneous emission of molecules are studied theoretically. From the proposed theory and numerical simulations, it is found that the self-pulsations originate in an interplay between stimulated emission and saturable absorption. A stability analysis demonstrates the crucial role of the photoabsorption in this process, which can be regulated by a proper choice of buffer molecules. Variations in the saturable absorption mediate a transition from damped oscillations to self-sustained pulsations. The role of propagation effects as well as of the interaction of co- and counter-propagating pulses is also investigated. Numerical simulations, demonstrating the theoretical findings, are performed for a model 3-level system and for an organic chromophore; 4-[N-(2-hydroxyethyl)-N-(methyl)amino phenyl]-4'-(6-hydroxyhexyl sulphonyl) stilbene.

  • 33. Popov, A. K.
    et al.
    Kimberg, Viktor V.
    KTH, Superseded Departments, Biotechnology. Institute of Physics, Russian Academy of Sciences, Russian.
    George, T. F.
    Large enhancement of fully resonant sum-frequency generation through quantum control via continuum states2004In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 69, no 4, p. 043816-1Article in journal (Refereed)
    Abstract [en]

    The enhancement of resonant sum-frequency generation through quantum control, which employs the continuum states, was discussed. The scheme employs all-resonant coupling and trade-off optimization of the constructive and destructive quantum interference effects in the higher-order and lower-order polarizations controlled by the overlap of two autoionizinglike laser-induced continuum structure. It was found that the analytical solution of coupled density-matrix equations were implemented for analysis of the solution of Maxwell's equation describing four-wave mixing. The results show that the feasibility of the nearly complete conversion of low-frequency radiation to sum frequency radiation was shown for the case of quasiresonant coupling.

  • 34.
    Savchenko, Viktoriia
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Federal University, Russian Federation.
    Zimin, Andrei
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Federal University, Russian Federation.
    Ignatova, Nina Yu.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Federal University, Russian Federation.
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Federal University, Russian Federation.
    Gelmukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Federal University, Russian Federation.
    Polyutov, S. P.
    Size-dependent blinking of molecular aggregate total emission2017In: 4th International School and Conference "Saint Petersburg OPEN 2017" on Optoelectronics, Photonics, Engineering and Nanostructures, Institute of Physics Publishing (IOPP), 2017, Vol. 917, no 6, article id 062051Conference paper (Refereed)
    Abstract [en]

    Molecular aggregates are well known for their customizable optical properties. Vibronic coupling in monomers forming such aggregates offers rich opportunities for property tuning. We study generic molecular aggregate models of growing complexity (from a dimer up to a decamer) and report how vibronic coupling affects aggregate fluorescence intensity. The total aggregate fluorescence intensity is a measure sensitive to both vibronic coupling and Coulomb coupling between monomer transition densities. Using an exact diagonalization approach in the two-particle basis set, we show how the interplay between Coulomb and vibronic coupling affects aggregate fluorescence. Moreover, for H-aggregates we predict a periodic variation of the fluorescence intensity with aggregate size and show that vibronic interaction decreases the effect.

  • 35.
    Ueda, K.
    et al.
    KTH, School of Biotechnology (BIO).
    Liu, X.-J.
    Prumper, G.
    Lischke, T.
    Tanaka, T.
    Hoshino, M.
    Tanaka, H.
    Minkov, Ivaylo
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Kimberg, Victor
    KTH, School of Biotechnology (BIO).
    Gelmukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Role of the recoil effect on two-center interference in x-ray photoionization2006In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 329, no 1-3, p. 329-337Article in journal (Refereed)
    Abstract [en]

    X-ray photoelectron spectra of the N-2 molecule are studied both experimentally and theoretically in the extended energy region up to 1 keV. The ratio of the photoionization cross sections for the gerade and ungerade core levels displays a modulation in the high energy region caused by the two-center interference, as predicted by Cohen and Fano (CF) in 1966. The physical background of this CF effect is the same as in Young's double-slit experiment. We have found that the interference pattern deviates significantly from the CF prediction. The origin of such a breakdown of the CF formula is the scattering of the photoelectron inside the molecule and the momentum transfer from the emitted fast photoelectron to the nuclei. Usually the recoil effect is small. We show that the electron recoil strongly affects the two-center interference pattern. Both stationary and dynamical aspects of the recoil effect shed light on the role of the momentum exchange in the two-center interference.

  • 36.
    Vaz da Cruz, Vinicius
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ertan, Emelie
    C. Couto, Rafael
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Eckert, Sebastian
    Fondell, Mattis
    Dantz, Marcus
    O'Cinneide, Brian
    Schmitt, Thorsten
    Pietzsch, Annette
    F. Guimarães, Freddy
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Gelmukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Odelius, Michael
    Föhlisch, Alexander
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    A study of the water molecule using frequency control over nuclear dynamics in resonant X-ray scattering2017In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 30, p. 19573-19589Article in journal (Refereed)
    Abstract [en]

    In this combined theoretical and experimental study we report a full analysis of the resonant inelastic X-ray scattering (RIXS) spectra of H2O, D2O and HDO. We demonstrate that electronically-elastic RIXS has an inherent capability to map the potential energy surface and to perform vibrational analysis of the electronic ground state in multimode systems. We show that the control and selection of vibrational excitation can be performed by tuning the X-ray frequency across core-excited molecular bands and that this is clearly reflected in the RIXS spectra. Using high level ab initio electronic structure and quantum nuclear wave packet calculations together with high resolution RIXS measurements, we discuss in detail the mode coupling, mode localization and anharmonicity in the studied systems.

  • 37.
    Velkov, Yasen
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Kimberg, Victor
    Kosugi, Nobuhiro
    Salek, Pawel
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Gel'mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Pseudo-resonance formation in X-ray absorption spectrum of oxygen moleculeManuscript (Other academic)
  • 38.
    Velkov, Yasen
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Kimberg, Victor
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Polyutov, Sergey
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Gel'mukhanov, Faris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Role of intramolecular vibrational redistribution on dynamics of cavityless lasingManuscript (Other academic)
1 - 38 of 38
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