Accurate X-ray Absorption Spectra near L- and M-Edges from Relativistic Four-Component Damped Response Time-Dependent Density Functional Theory

Autor: Kenneth Ruud, Stanislav Komorovsky, Michal Repisky, Lukas Konecny, Jan Vícha
Rok vydání: 2021
Předmět:
Zdroj: Inorganic Chemistry
ISSN: 1520-510X
0020-1669
DOI: 10.1021/acs.inorgchem.1c02412
Popis: The simulation of X-ray absorption spectra requires both scalar and spin-orbit (SO) relativistic effects to be taken into account, particularly near L- and M-edges where the SO splitting of core p and d orbitals dominates. Four-component Dirac-Coulomb Hamiltonian-based linear damped response time-dependent density functional theory (4c-DR-TDDFT) calculates spectra directly for a selected frequency region while including the relativistic effects variationally, making the method well suited for X-ray applications. In this work, we show that accurate X-ray absorption spectra near L-2,L-3- and M-4,M-5-edges of closed-shell transition metal and actinide compounds with different central atoms, ligands, and oxidation states can be obtained by means of 4c-DR-TDDFT. While the main absorption lines do not change noticeably with the basis set and geometry, the exchange-correlation functional has a strong influence with hybrid functionals performing the best. The energy shift compared to the experiment is shown to depend linearly on the amount of Hartee-Fock exchange with the optimal value being 60% for spectral regions above 1000 eV, providing relative errors below 0.2% and 2% for edge energies and SO splittings, respectively. Finally, the methodology calibrated in this work is used to reproduce the experimental L-2,L-3-edge X-ray absorption spectra of [RuCl2(DMSO)(2)(Im)(2)] and [WCl4(PMePh2)(2)], and resolve the broad bands into separated lines, allowing an interpretation based on ligand field theory and double point groups. These results support 4c-DR-TDDFT as a reliable method for calculating and analyzing X-ray absorption spectra of chemically interesting systems, advance the accuracy of state-of-the art relativistic DFT approaches, and provide a reference for benchmarking more approximate techniques.
Research Council of NorwayResearch Council of Norway [315822, 252569]; Ministry of Education, Youth and Sports of the Czech Republic -DKRVO [RP/CPS/2020/006]; Slovak Grant Agency VEGAVedecka grantova agentura MSVVaS SR a SAV (VEGA) [2/0135/21, APVV-19-0516]; Slovak Grant Agency APVVSlovak Research and Development Agency [2/0135/21, APVV-19-0516]; UNINETT Sigma2, the National Infrastructure for High Performance Computing and Data Storage in Norway [NN4654K]; Ministry of Education, Youth and Sports of the Czech Republic through the e-INFRA CZ [90140]
RP/CPS/2020/006; NN4654K, Sigma2; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: 90140; Norges Forskningsråd: 252569, 315822; Vedecká Grantová Agentúra MŠVVaŠ SR a SAV, VEGA: 2/0135/21, APVV-19-0516
Databáze: OpenAIRE
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