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Publications (10 of 159) Show all publications
Rachlew, E. (2018). Fragmentation of imidazole, pyrimidine and purine induced by core ionization: Significance of small-scale chamical environment. Journal of Photochemistry and Photobiology A: Chemistry,, 356, 283-289, Article ID 2018.01.003.
Open this publication in new window or tab >>Fragmentation of imidazole, pyrimidine and purine induced by core ionization: Significance of small-scale chamical environment
2018 (English)In: Journal of Photochemistry and Photobiology A: Chemistry,, ISSN ISSN 1010-6030, Vol. 356, p. 283-289, article id 2018.01.003Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-224641 (URN)10.1016 (DOI)
Note

QC 20180327

Available from: 2018-03-21 Created: 2018-03-21 Last updated: 2018-03-27Bibliographically approved
Takahashi, O., Kooser, K., Ha, D. T., Myllynen, H., Laksman, J., Rachlew, E. & Kukk, E. (2018). Site-selective bond scission of methylbenzoate following core excitation. Physical Chemistry, Chemical Physics - PCCP, 20(14), 9591-9599
Open this publication in new window or tab >>Site-selective bond scission of methylbenzoate following core excitation
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2018 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 14, p. 9591-9599Article in journal (Refereed) Published
Abstract [en]

The chemical bond scission of methylbenzoate (C6H5CO2CH3) following core excitation at the C and O K edges was examined from partial ion yield measurements across these edges using synchrotron radiation. Site-specific scission of the C-O bonds was observed at both edges. Theoretical X-ray absorption spectra (XAS) were obtained using density functional theory. Peak assignments in the observed spectra were found to be consistent with the theory. From core-excited state dynamics calculations, an elongation of the C-O bond was predicted and provides an explanation of the observed partial ion yield enhancement of CH3+ and C6H5CO+ at the core-excited resonances at both edges.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
National Category
Chemical Sciences Physical Sciences
Identifiers
urn:nbn:se:kth:diva-226759 (URN)10.1039/c7cp08428e (DOI)000429205700058 ()29578226 (PubMedID)2-s2.0-85045112931 (Scopus ID)
Note

QC 20180503

Available from: 2018-05-03 Created: 2018-05-03 Last updated: 2018-05-03Bibliographically approved
Frassinetti, L., Saarelma, S., Lomas, P., Nunes, I., Rimini, F., Beurskens, M. N., . . . Stefanikova, E. (2017). Dimensionless scalings of confinement, heat transport and pedestal stability in JET-ILW and comparison with JET-C. Plasma Physics and Controlled Fusion, 59(1), Article ID 014014.
Open this publication in new window or tab >>Dimensionless scalings of confinement, heat transport and pedestal stability in JET-ILW and comparison with JET-C
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2017 (English)In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 59, no 1, article id 014014Article in journal (Refereed) Published
Abstract [en]

Three dimensionless scans in the normalized Larmor radius rho*, normalized collisionality nu* and normalized plasma pressure beta have been performed in JET with the ITER-like wall (JET-ILW). The normalized energy confinement and the thermal diffusivity exhibit a scaling with rho* consistent with the earlier results obtained in the carbon wall JET (JET-C) and with a gyro-Bohm scaling. In the pedestal, experimental results show that the stability is not dependent on rho*, qualitatively in agreement with the peeling-ballooning (P-B) model. The nu* dimensionless scaling shows that JET-ILW normalized confinement has a stronger dependence on collisionality than JET-C. This leads to a reduction of the difference in the confinement between JET-ILW and JET-C to approximate to 10% at low nu*. The pedestal stability shows an improvement with decreasing nu*. This is ascribed to the increase of the bootstrap current, to the reduction of the pedestal width and to the reduction of the relative shift between pedestal density and temperature position. The beta dimensionless scan shows that, at low collisionality, JET-ILW normalized confinement has no clear dependence with beta, in agreement with part of the earlier scalings. At high collisionality, a reduction of the normalized confinement with increasing beta is observed. This behaviour is driven mainly by the pedestal where the stability is reduced with increasing beta. The P-B analysis shows that the stability reduction with increasing beta at high nu* is due to the destabilizing effect of the increased relative shift.

Place, publisher, year, edition, pages
Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England. [Frassinetti, L.; Stefanikova, E.] KTH Royal Inst Technol, Div Fus Plasma Phys, SE-10691 Stockholm, Sweden. [Saarelma, S.; Lomas, P.; Rimini, F.; Drewelow, P.; Flanagan, J.; Garzotti, L.; Giroud, C.; Hawks, N.; Joffrin, E.; Kempenaars, M.; Kim, Hyun-Tae; Kruezi, U.; Lupelli, I.; Maggi, C. F.; Menmuir, S.; Romanelli, M.] Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England. [Nunes, I.; Meneses, L.] Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, P-1049001 Lisbon, Portugal. [Beurskens, M. N. A.] Max Planck Inst Plasma Phys, D-17491 Greifswald, Germany. [Boom, J. E.] Max Planck Inst Plasma Phys, Boltzmannstr 2, D-85748 Garching, Germany. [de la Luna, E.] CIEMAT, Lab Nacl Fus, Madrid 28040, Spain. [Delabie, E.] Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. [Loarte, A.] ITER Org, Plasma Operat Directorate, F-13115 St Paul Les Durance, France. [Lomanowski, B.] Aalto Univ, TEKES, Espoo, Finland. [Bilkova, P.; Peterka, M.] AS CR, Vvi, Inst Plasma Phys, Prague, Czech Republic. [Rachlew, E.] KTH Royal Inst Technol, Dept Phys, SE-10691 Stockholm, Sweden.: , 2017
Keywords
JET-ILW, dimensionless scaling, pedestal, confinement, pedestal stability, heat transport
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-196967 (URN)10.1088/0741-3335/59/1/014014 (DOI)000386594300014 ()2-s2.0-85006117570 (Scopus ID)
Note

QC 20161213

Available from: 2016-12-13 Created: 2016-11-28 Last updated: 2017-11-29Bibliographically approved
Horvath, A. & Rachlew (Källne), E. (2016). Nuclear power in the 21st century: Challenges and possibilities. Ambio, 45(Suppl. 1), 38-49
Open this publication in new window or tab >>Nuclear power in the 21st century: Challenges and possibilities
2016 (English)In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 45, no Suppl. 1, p. 38-49Article, review/survey (Refereed) Published
Abstract [en]

The current situation and possible future developments for nuclear power—including fission and fusion processes—is presented. The fission nuclear power continues to be an essential part of the low-carbon electricity generation in the world for decades to come.

There are breakthrough possibilities in the development of new generation nuclear reactors where the life-time of the nuclear waste can be reduced to some hundreds of years instead of the present time-scales of hundred thousand of years. Research on the fourth generation reactors is needed for the realisation of this development. For the fast nuclear reactors, a substantial research and development effort is required in many fields—from material sciences to safety demonstration—to attain the envisaged goals. Fusion provides a long-term vision for an efficient energy production. The fusion option for a nuclear reactor for efficient production of electricity has been set out in a focussed European programme including the international project of ITER after which a fusion electricity DEMO reactor is envisaged.

Place, publisher, year, edition, pages
Springer, 2016
Keywords
Fission, Fusion, Fusion plasma physics, Nuclear power, Nuclear waste, Reactor physics
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kth:diva-181327 (URN)10.1007/s13280-015-0732-y (DOI)000366623100006 ()26667059 (PubMedID)2-s2.0-84950281569 (Scopus ID)
Note

QC 20160224

Available from: 2016-02-01 Created: 2016-02-01 Last updated: 2017-11-30Bibliographically approved
Rachlew, E. (2016). Study on a hypothetical replacement of nuclear electricity by wind power in Sweden. European Physics Journal Plus, 131, 16173-16178
Open this publication in new window or tab >>Study on a hypothetical replacement of nuclear electricity by wind power in Sweden
2016 (English)In: European Physics Journal Plus, Vol. 131, p. 16173-16178Article in journal (Refereed) Published
Abstract [en]

The Swedish electricity supply system benefits strongly from the natural conditions which allow a high share of hydroelectricity. A complete supply is, however, not possible. Up to now nuclear power is the other workshop horse to serve the country with electricity. Thus, electricity production in Sweden is basically CO2-free and Sweden has reached an environmental status which others in Europe plan to reach in 2050. Furthermore, there is an efficient exchange within the Nordic countries, Nordpol, which can ease possible capacity problems during dry cold years. In this study we investigate to what extent and with what consequences the base load supply of nuclear power can be replaced by intermittent wind power. Such a scenario leads unavoidably to high wind power installations. It is shown that hydroelectricity can not completely smooth out the fluctuations of wind power and an additional back-up system using fossil fuel is necessary. From the  operational dynamics, this system has to be based on gas. The back-up system cannot be replaced by a storage using surplus electricity from wind power. The surplus is too little. To overcome this, further strong extension of wind power is necessary which leads, however, to a reduction of the use of hydroelectricity if the annual consumption is kept constant. In this case a fossil-free energy form is replaced by another, however, more complex one. A mix of wind power at 22.3 GW plus a gas based back-up system with 8.6 GW producing together 64.8 TWh would replace the present infrastructure with 9 GW nuclear power producing 63.8 TWh electricty. The specific CO2-emission increases to the double in this case. Pumped storage for the exclusive supply of Sweden does not seen to be a meaningful investment.

Place, publisher, year, edition, pages
Springer, 2016
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-224640 (URN)10.1140/epjp/i2016-161738-16178 (DOI)
Note

QC 20180327

Available from: 2018-03-21 Created: 2018-03-21 Last updated: 2018-05-24Bibliographically approved
Bengtsson, L., Rachlew (Källne), E. & Wagner, F. (2016). Sustainable energy supply and consumption by 2050 and outlook towards the end of the century: Possible scientific breakthroughs. Ambio, 45(Suppl. 1):), 1-4
Open this publication in new window or tab >>Sustainable energy supply and consumption by 2050 and outlook towards the end of the century: Possible scientific breakthroughs
2016 (English)In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 45, no Suppl. 1):, p. 1-4Article, review/survey (Refereed) Published
Place, publisher, year, edition, pages
Springer, 2016
Keywords
Low carbon energy supply and consumption
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kth:diva-181328 (URN)10.1007/s13280-015-0735-8 (DOI)000366623100001 ()26667054 (PubMedID)2-s2.0-84950241965 (Scopus ID)
Note

QC 20160224

Available from: 2016-02-01 Created: 2016-02-01 Last updated: 2017-11-30Bibliographically approved
Itala, E., Kooser, K., Rachlew, E., Levola, H., Ha, D. T. & Kukk, E. (2015). Gas-phase study on uridine: Conformation and X-ray photofragmentation. Journal of Chemical Physics, 142(19), Article ID 194303.
Open this publication in new window or tab >>Gas-phase study on uridine: Conformation and X-ray photofragmentation
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2015 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 142, no 19, article id 194303Article in journal (Refereed) Published
Abstract [en]

Fragmentation of RNA nucleoside uridine, induced by carbon 1s core ionization, has been studied. The measurements by combined electron and ion spectroscopy have been performed in gas phase utilizing synchrotron radiation. As uridine is a combination of d-ribose and uracil, which have been studied earlier with the same method, this study also considers the effect of chemical environment and the relevant functional groups. Furthermore, since in core ionization the initial core hole is always highly localized, charge migration prior to fragmentation has been studied here. This study also demonstrates the destructive nature of core ionization as in most cases the C 1s ionization of uridine leads to concerted explosions producing only small fragments with masses <= 43 amu. In addition to fragmentation patterns, we found out that upon evaporation the sugar part of the uridine molecule attains hexagonal form.

Keywords
Carbon, Functional groups, Gases, Ionization, Synchrotron radiation, Carbon 1s, Charge migration, Core hole, Core ionization, Effect of chemicals, Fragmentation patterns, Ion spectroscopies, Photofragmentation
National Category
Physical Sciences Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-169260 (URN)10.1063/1.4919878 (DOI)000355006200020 ()26001457 (PubMedID)2-s2.0-84930226850 (Scopus ID)
Funder
Swedish Research Council
Note

QC 20150615

Available from: 2015-06-15 Created: 2015-06-12 Last updated: 2017-12-04Bibliographically approved
Kukk, E., Ha, D. T., Wang, Y., Piekarski, D. G., Diaz-Tendero, S., Kooser, K., . . . Martin, F. (2015). Internal energy dependence in x-ray-induced molecular fragmentation: An experimental and theoretical study of thiophene. Physical Review A. Atomic, Molecular, and Optical Physics, 91(4), Article ID 043417.
Open this publication in new window or tab >>Internal energy dependence in x-ray-induced molecular fragmentation: An experimental and theoretical study of thiophene
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2015 (English)In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 91, no 4, article id 043417Article in journal (Refereed) Published
Abstract [en]

A detailed experimental and theoretical investigation of the dynamics leading to fragmentation of doubly ionized molecular thiophene is presented. Dissociation of double-ionized molecules was induced by S 2p core photoionization and the ionic fragments were detected in coincidence with Auger electrons from the core-hole decay. Rich molecular dynamics was observed in electron-ion-ion coincidence maps exhibiting ring breaks accompanied by hydrogen losses and/or migration. The probabilities of various dissociation channels were seen to be very sensitive to the internal energy of the molecule. Theoretical simulations were performed by using the semiempirical self-consistent charge-density-functional tight-binding method. By running thousands of these simulations, the initial conditions encountered in the experiment were properly taken into account, including the systematic dependencies on the internal (thermal) energy. This systematic approach, not affordable with first-principle methods, provides a good overall description of the complex molecular dynamics observed in the experiment and shows good promise for applicability to larger molecules or clusters, thus opening the door to systematic investigations of complex dynamical processes occurring in radiation damage.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-171693 (URN)10.1103/PhysRevA.91.043417 (DOI)000353448500003 ()2-s2.0-84928783179 (Scopus ID)
Note

QC 20150807

Available from: 2015-08-07 Created: 2015-08-05 Last updated: 2017-12-04Bibliographically approved
Levola, H., Itala, E., Schlesier, K., Kooser, K., Laine, S., Laksman, J., . . . Kukk, E. (2015). Ionization-site effects on the photofragmentation of chloro- and bromoacetic acid molecules. Physical Review A. Atomic, Molecular, and Optical Physics, 92(6), Article ID 063409.
Open this publication in new window or tab >>Ionization-site effects on the photofragmentation of chloro- and bromoacetic acid molecules
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2015 (English)In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 92, no 6, article id 063409Article in journal (Refereed) Published
Abstract [en]

Fragmentation of gas-phase chloro-and bromoacetic acid samples, particularly its dependency on the atomic site of the initial core ionization, was studied in photoelectron-photoion-photoion coincidence (PEPIPICO) measurements. The fragmentation was investigated after ionizing carbon 1s and bromine 3d or chlorine 2p core orbitals. It was observed that the samples had many similar fragmentation pathways and that their relative weights depended strongly on the initial ionization site. Additional Auger PEPIPICO measurements revealed a clear dependence of fragment pair intensities on the kinetic energy of the emitted Auger electrons. The modeled and measured Auger electron spectra indicated that the average internal energy of the molecule was larger following the carbon 1s core-hole decay than after the decay of the halogen core hole. This difference in the internal energies was found to be the source of the site-dependent photofragmentation behavior.

Place, publisher, year, edition, pages
American Physical Society, 2015
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-180216 (URN)10.1103/PhysRevA.92.063409 (DOI)000366083100008 ()2-s2.0-84950111139 (Scopus ID)
Note

QC 20160119

Available from: 2016-01-19 Created: 2016-01-08 Last updated: 2017-11-30Bibliographically approved
Kukk, E., Ha, D. T., Wang, Y., Piekarski, D. G., Diaz-Tendero, S., Kooser, K., . . . Martin, F. (2015). Molecular dynamics of photodissociation: towards more complex systems. In: XXIX INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC, AND ATOMIC COLLISIONS (ICPEAC2015), PTS 1-12: . Paper presented at 29th International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC), JUL 22-28, 2015, Toledo, SPAIN. Institute of Physics Publishing (IOPP), Article ID UNSP 112105.
Open this publication in new window or tab >>Molecular dynamics of photodissociation: towards more complex systems
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2015 (English)In: XXIX INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC, AND ATOMIC COLLISIONS (ICPEAC2015), PTS 1-12, Institute of Physics Publishing (IOPP), 2015, article id UNSP 112105Conference paper, Published paper (Refereed)
Abstract [en]

We present a combined experimental and theoretical study of the photodissociation of thiophene molecule using energy-resolved electron-ion-ion coincidence technique and self-consistent charge density functional tight-binding theory combined with a statistical approach. The observed complex molecular dynamics with many internal-energy-dependent fragmentation pathways is successfully described by the theoretical simulations.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2015
Series
Journal of Physics Conference Series, ISSN 1742-6588 ; 635
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-180392 (URN)10.1088/1742-6596/635/11/112105 (DOI)000366407000684 ()2-s2.0-84948844182 (Scopus ID)
Conference
29th International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC), JUL 22-28, 2015, Toledo, SPAIN
Note

QC 20160114

Available from: 2016-01-14 Created: 2016-01-13 Last updated: 2016-01-14Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-7389-5501

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