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Staemmler V. Wavefunction-based quantum-chemical ab initiocalculations for core electron binding energies of small open shell molecules. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:354004. [PMID: 35700722 DOI: 10.1088/1361-648x/ac78b9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
Core electron binding energies (CEBEs), i.e. ionization energies of 1s core orbitals, are calculated by means of wavefunction-based quantum-chemicalab initiomethods for a series of small open-shell molecules containing first-row atoms. The calculations are performed in three steps: (a) Koopmans' theorem, where the orbitals of the electronic ground state are used unchanged also for the ions, (b) Hartree-Fock or self consistent field (SCF) approximation in which the orbitals are allowed to relax after 1s ionization (ΔSCF), (c) dynamic correlation effects on top of SCF. For open-shell molecules 1s ionization leads to ions in several spin states, mostly to a pair of a triplet and a singlet state. In several cases one or both of these ionic states are only poorly described by a single-reference SCF wavefunction, therefore a multi-reference complete active space self consistent field (CAS-SCF) wavefunction is used instead. The correlation effects are evaluated by means of our multi-reference coupled electron pair approximation program. The accuracy of the calculated CEBEs is in the order of 0.1-0.4 eV. This is in agreement with experimental results for NO and O2. But there exist only very few gas phase data for CEBEs of open-shell molecules.
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Affiliation(s)
- Volker Staemmler
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, D-44780 Bochum, Germany
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Goldsztejn G, Guillemin R, Marchenko T, Travnikova O, Céolin D, Journel L, Simon M, Piancastelli MN, Püttner R. Simulation of Auger decay dynamics in the hard X-ray regime: HCl as a showcase. Phys Chem Chem Phys 2022; 24:6590-6604. [PMID: 35234229 DOI: 10.1039/d1cp05662j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Auger decay after photoexcitation or photoemission of an electron from a deep inner shell in the hard X-ray regime can be rather complex, implying a multitude of phenomena such as multiple-step cascades, post-collision interaction (PCI), and electronic state-lifetime interference. Furthermore, in a molecule nuclear motion can also be triggered. Here we discuss a comprehensive theoretical method which allows us to analyze in great detail Auger spectra measured around an inner-shell ionization threshold. HCl photoexcited or photoionized around the deep Cl 1s threshold is chosen as a showcase. Our method allows calculating Auger cross sections considering the nature of the ground, intermediate and final states (bound or dissociative), and the evolution of the relaxation process, including both electron and nuclear dynamics. In particular, we show that we can understand and reproduce a so-called experimental 2D-map, consisting of a series of resonant Auger spectra measured at different photon energies, therefore obtaining a detailed picture of all above-mentioned dynamical phenomena at once.
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Affiliation(s)
- G Goldsztejn
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France.
| | - R Guillemin
- Sorbonne Université, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005 Paris, France. .,Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex, France
| | - T Marchenko
- Sorbonne Université, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005 Paris, France. .,Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex, France
| | - O Travnikova
- Sorbonne Université, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005 Paris, France. .,Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex, France
| | - D Céolin
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex, France
| | - L Journel
- Sorbonne Université, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005 Paris, France. .,Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex, France
| | - M Simon
- Sorbonne Université, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005 Paris, France. .,Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex, France
| | - M N Piancastelli
- Sorbonne Université, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005 Paris, France. .,Department of Physics and Astronomy, Uppsala University, SE-751 20 Uppsala, Sweden
| | - R Püttner
- Fachbereich Physik, Freie Universität Berlin, D-14195 Berlin, Germany.
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3
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Sen A, de Souza B, Huntington LMJ, Krupička M, Neese F, Izsák R. An efficient pair natural orbital based configuration interaction scheme for the calculation of open-shell ionization potentials. J Chem Phys 2018; 149:114108. [DOI: 10.1063/1.5048688] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Avijit Sen
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Bernardo de Souza
- Max-Planck-Institute for Chemical Energy Conversion, Mülheim an der Ruhr, Germany
- Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Lee M. J. Huntington
- Max-Planck-Institute for Chemical Energy Conversion, Mülheim an der Ruhr, Germany
| | - Martin Krupička
- Max-Planck-Institute for Chemical Energy Conversion, Mülheim an der Ruhr, Germany
- University of Chemistry and Technology, Prague, Czech Republic
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Róbert Izsák
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
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