Change search
Link to record
Permanent link

Direct link
BETA
Publications (4 of 4) Show all publications
Brumboiu, I., Eriksson, O. & Norman, P. (2019). Atomic photoionization cross sections beyond the electric dipole approximation. Journal of Chemical Physics, 150(4), Article ID 044306.
Open this publication in new window or tab >>Atomic photoionization cross sections beyond the electric dipole approximation
2019 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 150, no 4, article id 044306Article in journal (Refereed) Published
Abstract [en]

A methodology is developed to compute photoionization cross sections beyond the electric dipole approximation from response theory, using Gaussian type orbitals and plane waves for the initial and final states, respectively. The methodology is applied to compute photoionization cross sections of atoms and ions from the first four rows of the periodic table. Analyzing the error due to the plane wave description of the photoelectron, we find kinetic energy and concomitant photon energy thresholds above which the plane wave approximation becomes applicable. The correction introduced by going beyond the electric dipole approximation increases with photon energy and depends on the spatial extension of the initial state. In general, the corrections are below 10% for most elements, at a photon energy reaching up to 12 keV. 2019 Author(s).

Place, publisher, year, edition, pages
AMER INST PHYSICS, 2019
Keywords
LEUZE M, 1994, MOLECULAR PHYSICS, V83, P655
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-244111 (URN)10.1063/1.5083649 (DOI)000457414600056 ()30709292 (PubMedID)2-s2.0-85060862106 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation, KAW-2013.0020Swedish Research Council, 621-2014-4646
Note

QC 20190219

Available from: 2019-02-19 Created: 2019-02-19 Last updated: 2019-02-19Bibliographically approved
Zhang, T., Brumboiu, I., Lanzilotto, V., Grazioli, C., Guarnaccio, A., Johansson, F. O., . . . Puglia, C. (2019). Electronic structure modifications induced by increased molecular complexity: from triphenylamine to m-MTDATA. Physical Chemistry, Chemical Physics - PCCP, 21(32), 17959-17970
Open this publication in new window or tab >>Electronic structure modifications induced by increased molecular complexity: from triphenylamine to m-MTDATA
Show others...
2019 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 21, no 32, p. 17959-17970Article in journal (Refereed) Published
Abstract [en]

The starburst pi-conjugated molecule 4,4 ',4 ''-tris(N-3-methylphenyl-N-phenyl-amino)triphenylamine (C57H48N4, m-MTDATA), based on triphenylamine (TPA) building blocks, is widely used in optoelectronic devices due to its good electron-donor characteristics. The electronic structure of m-MTDATA was investigated for the first time in the gas phase by means of PhotoElectron Spectroscopy (PES) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. The combination of Density Functional Theory (DFT) calculations with the experimental spectra provides a comprehensive description of the molecular electronic structure. Moreover, by comparing the results with previous TPA measurements, we could shed light on how the electronic structure evolves when the molecular size is increased. We found that the C 1s photoelectron spectra of m-MTDATA and TPA are similar, due to the balance of the counter-acting effects of the electronegativity of the N atoms and the delocalization of the amine lone-pair electrons. In contrast, the increased number of N atoms (i.e. N lone pairs) in m-MTDATA determines a three-peak feature in the outermost valence binding energy region with strong contributions by the N 2p(z) orbitals. We also obtained a decrease of the HOMO-LUMO gap for m-MTDATA, which points to improved electron donating properties of m-MTDATA with respect to TPA.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2019
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:kth:diva-259438 (URN)10.1039/c9cp02423a (DOI)000481777100046 ()31384854 (PubMedID)2-s2.0-85071311683 (Scopus ID)
Note

QC 20190924

Available from: 2019-09-24 Created: 2019-09-24 Last updated: 2019-09-24Bibliographically approved
Brumboiu, I., Haldar, S., Luder, J., Eriksson, E., Herper, H. C., Brena, B. & Sanyal, B. (2019). Ligand Effects on the Linear Response Hubbard U: The Case of Transition Metal Phthalocyanines. Journal of Physical Chemistry A, 123(14), 3214-3222
Open this publication in new window or tab >>Ligand Effects on the Linear Response Hubbard U: The Case of Transition Metal Phthalocyanines
Show others...
2019 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 123, no 14, p. 3214-3222Article in journal (Refereed) Published
Abstract [en]

It is established that density functional theory (DFT) + U is a better choice compared to DFT for describing the correlated electron metal center in organometallics. The value of the Hubbard U parameter may be determined from linear response, either by considering the response of the metal site alone or by additionally considering the response of other sites in the compound. We analyze here in detail the influence of ligand shells of increasing size on the U parameter calculated from the linear response for five transition metal phthalocyanines. We show that the calculated multiple-site U ligand atoms that are mainly responsible for this difference are is larger than the single-site U by as much as 1 eV and the ligand atoms that are mainly responsible for this difference are the isoindole nitrogen atoms directly bonded to the central metal atom. This suggests that a different U value may be required for computations of chemisorbed molecules compared to physisorbed and gas-phase cases.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-251492 (URN)10.1021/acs.jpca.8b11940 (DOI)000464768100011 ()30892039 (PubMedID)2-s2.0-85064226482 (Scopus ID)
Note

QC 20190516

Available from: 2019-05-16 Created: 2019-05-16 Last updated: 2019-05-16Bibliographically approved
Zhang, T., Brumboiu, I., Lanzilotto, V., Luder, J., Grazioli, C., Giangrisostomi, E., . . . Puglia, C. (2017). Conclusively Addressing the CoPc Electronic Structure: A Joint Gas-Phase and Solid-State Photoemission and Absorption Spectroscopy Study. The Journal of Physical Chemistry C, 121(47), 26372-26378
Open this publication in new window or tab >>Conclusively Addressing the CoPc Electronic Structure: A Joint Gas-Phase and Solid-State Photoemission and Absorption Spectroscopy Study
Show others...
2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 47, p. 26372-26378Article in journal (Refereed) Published
Abstract [en]

The occupied and empty densities of states of cobalt phthalocyanine (CoPc) were investigated by photoelectron and X-ray absorption spectroscopies in the gas phase and in thin films deposited on a Au(111) surface. The comparison between the gas-phase results and density functional theory single-molecule simulations confirmed that the CoPc ground state is correctly described by the (2)A(1g) electronic configuration. Moreover, photon-energy-dependent valence photoemission spectra of both the gas phase and thin film confirmed the atomic character of the highest occupied molecular orbital as being derived from the organic ligand, with dominant contributions from the carbon atoms. Multiplet ligand-field theory was employed to simulate the Co L-edge X-ray absorption spectroscopy results.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2017
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:kth:diva-220483 (URN)10.1021/acs.jpcc.7b08524 (DOI)000417228500026 ()2-s2.0-85037091491 (Scopus ID)
Funder
Swedish Research CouncilCarl Tryggers foundation
Note

QC 20180104

Available from: 2018-01-04 Created: 2018-01-04 Last updated: 2018-01-04Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1671-8298

Search in DiVA

Show all publications