Open AccessRelativistic MulticonfigurationalAb InitioCalculation of Uranyl 3d4f Resonant Inelastic X-ray Scattering
Author(s) -
Robert Polly,
Bianca Schacherl,
Jörg Rothe,
T. Vitova
Publication year - 2021
Publication title -
inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 233
eISSN - 1520-510X
pISSN - 0020-1669
DOI - 10.1021/acs.inorgchem.1c02364
Subject(s) - chemistry , ab initio , resonant inelastic x ray scattering , atomic physics , atomic orbital , electronic structure , ab initio quantum chemistry methods , scattering , spectral line , k edge , uranyl , emission spectrum , relativistic quantum chemistry , inelastic scattering , electron , physics , inelastic neutron scattering , computational chemistry , molecule , ion , nuclear physics , quantum mechanics , organic chemistry
We applied relativistic multiconfigurational all-electron ab initio calculations including the spin-orbit interaction to calculate the 3d4f resonant inelastic X-ray scattering (RIXS) map (3d 3/2 → 5f 5/2 U M 4 absorption edge and 4f 5/2 → 3d 3/2 U M β emission) of uranyl (UO 2 2+ ). The calculated data are in excellent agreement with experimental results and allow a detailed understanding of the observed features and an unambiguous assignment of all involved intermediate and final states. The energies corresponding to the maxima of the resonant emission and the non-resonant (normal) emission were determined with high accuracy, and the corresponding X-ray absorption near edge structure spectra extracted at these two positions were simulated and agree well with the measured data. With the high quality of our theoretical data, we show that the cause of the splitting of the three main peaks in emission is due to the fine structure splitting of the 4f orbitals induced through the trans di-oxo bonds in uranyl and that we are able to obtain direct information about the energy differences between the 5f and 4f orbitals: Δ5f δ/ϕ - 4f δ/ϕ, Δ5f π* - 4f π, and Δ5f σ* - 4f σ from the 3d4f RIXS map. RIXS maps contain a wealth of information, and ab initio calculations facilitate an understanding of their complex structure in a clear and transparent way. With these calculations, we show that the multiconfigurational protocol, which is nowadays applied as a standard tool to study the X-ray spectra of transition metal complexes, can be extended to the calculation of RIXS maps of systems containing actinides.