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Preuße M, Bokarev SI, Aziz SG, Kühn O. Towards an ab initio theory for metal L-edge soft X-ray spectroscopy of molecular aggregates. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2016; 3:062601. [PMID: 27679809 PMCID: PMC5010561 DOI: 10.1063/1.4961953] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/03/2016] [Indexed: 06/06/2023]
Abstract
The Frenkel exciton model was adapted to describe X-ray absorption and resonant inelastic scattering spectra of polynuclear transition metal complexes by means of the restricted active space self-consistent field method. The proposed approach allows to substantially decrease the requirements on computational resources if compared to a full supermolecular quantum chemical treatment. This holds true, in particular, in cases where the dipole approximation to the electronic transition charge density can be applied. The computational protocol was applied to the calculation of X-ray spectra of the hemin complex, which forms dimers in aqueous solution. The aggregation effects were found to be comparable to the spectral alterations due to the replacement of the axial ligand by solvent molecules.
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Affiliation(s)
- Marie Preuße
- Institut für Physik, Universität Rostock , Albert-Einstein-Str. 23-24, 18059 Rostock, Germany
| | - Sergey I Bokarev
- Institut für Physik, Universität Rostock , Albert-Einstein-Str. 23-24, 18059 Rostock, Germany
| | - Saadullah G Aziz
- Chemistry Department, Faculty of Science, King Abdulaziz University , 21589 Jeddah, Saudi Arabia
| | - Oliver Kühn
- Institut für Physik, Universität Rostock , Albert-Einstein-Str. 23-24, 18059 Rostock, Germany
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Golnak R, Xiao J, Atak K, Unger I, Seidel R, Winter B, Aziz EF. Undistorted X-ray Absorption Spectroscopy Using s-Core-Orbital Emissions. J Phys Chem A 2016; 120:2808-14. [PMID: 27101344 DOI: 10.1021/acs.jpca.6b01699] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Detection of secondary emissions, fluorescence yield (FY), or electron yield (EY), originating from the relaxation processes upon X-ray resonant absorption has been widely adopted for X-ray absorption spectroscopy (XAS) measurements when the primary absorption process cannot be probed directly in transmission mode. Various spectral distortion effects inherent in the relaxation processes and in the subsequent transportation of emitted particles (electron or photon) through the sample, however, undermine the proportionality of the emission signals to the X-ray absorption coefficient. In the present study, multiple radiative (FY) and nonradiative (EY) decay channels have been experimentally investigated on a model system, FeCl3 aqueous solution, at the excitation energy of the Fe L-edge. The systematic comparisons between the experimental spectra taken from various decay channels, as well as the comparison with the theoretically simulated Fe L-edge XA spectrum that involves only the absorption process, indicate that the detection of the Fe 3s → 2p partial fluorescence yield (PFY) gives rise to the true Fe L-edge XA spectrum. The two key characteristics generalized from this particular decay channel-zero orbital angular momentum (i.e., s orbital) and core-level emission-set a guideline for obtaining undistorted X-ray absorption spectra in the future.
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Affiliation(s)
- Ronny Golnak
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany.,Department of Chemistry, Free University Berlin , Takustrasse 3, 14195 Berlin, Germany
| | - Jie Xiao
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Kaan Atak
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany.,Department of Physics, Free University Berlin , Arnimallee 14, 14195 Berlin, Germany
| | - Isaak Unger
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Robert Seidel
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Bernd Winter
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Emad F Aziz
- Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany.,Department of Physics, Free University Berlin , Arnimallee 14, 14195 Berlin, Germany
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Seidel R, Atak K, Thürmer S, Aziz EF, Winter B. Ti3+ Aqueous Solution: Hybridization and Electronic Relaxation Probed by State-Dependent Electron Spectroscopy. J Phys Chem B 2015. [DOI: 10.1021/acs.jpcb.5b03337] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert Seidel
- Institute
of Methods for Material Development, Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse
15, D-12489 Berlin, Germany
| | - Kaan Atak
- Institute
of Methods for Material Development, Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse
15, D-12489 Berlin, Germany
| | - Stephan Thürmer
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Emad F. Aziz
- Institute
of Methods for Material Development, Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse
15, D-12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, D-14159 Berlin, Germany
| | - Bernd Winter
- Institute
of Methods for Material Development, Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse
15, D-12489 Berlin, Germany
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