Abstract
A scheme for simulations of resonant inelastic X-ray scattering (RIXS) cross-sections within time-dependent density functional theory (TD-DFT) applying the restricted subspace approximation (RSA) is presented. Therein both occupied core and valence Kohn-Sham orbitals are included in the donor-space, while the accepting virtual orbital space in the linear response TD-DFT equations is restricted to efficiently compute both the valence- and core-excited states of the many electron system. This yields a consistent description of all states contributing to the RIXS scattering process within a single calculation. The introduced orbital truncation allows to automatize the method and facilitates RIXS simulations for systems considerably larger than ones accessible with wave-function based methods. Using the nitrogen K-edge RIXS spectra of 2-thiopyridone and its deprotonated anion as a showcase, the method is benchmarked for different exchange-correlation functionals, the impact of the RSA is evaluated, and the effects of explicit solvation are discussed. Improvements compared to simulations in the frozen orbital approximation are also assessed. The general applicability of the framework is further tested by comparison to experimental data from the literature. The use of TD-DFT core-excited states to the calculation of vibrationally resolved RIXS spectra is also investigated by combining potential energy scans along relevant coordinates with wave packet simulations.
Highlights
Extracting chemical and physical insight from such intricate spectroscopies, often relies on an extensive computational effort in terms of electronic structure and spectral simulations
In this work we investigate the applicability of LR-timedependent density functional theory (TD-DFT) within the Restricted Subspace Approximation[29] (RSA) to K-edge RIXS spectroscopy
Results obtained with TD-DFT are expected to display a dependence on the exchange–correlation functional employed
Summary
Extracting chemical and physical insight from such intricate spectroscopies, often relies on an extensive computational effort in terms of electronic structure and spectral simulations. By solving the response equations with restricted donor and acceptor orbital spaces, one can obtain a full set of orthogonal valence- and core-excited states suitable for the calculation of the transition dipole moments necessary for specifying the Kramers–Heisenberg amplitudes in eqn (5).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
