Core–valence-separated coupled-cluster-singles-and-doubles complex-polarization-propagator approach to X-ray spectroscopies. Issue 5 (3rd September 2019)

• Record Type: Journal Article
• Authors: Faber, Rasmus; Coriani, Sonia
• Is Part Of: Physical chemistry chemical physics. Volume 22:Issue 5(2020)
• Page Start: 2642
• Page End: 2647
• Publication Date: 2019-09-03
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c9cp03696b
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The iterative subspace algorithm to solve the CCSD complex linear response equations has been modified to include a core–valence separation projection step to overcome convergence problems. Illustrative results are reported for XAS, XCD, XES and RIXS. Abstract : The iterative subspace algorithm to solve the complex linear response equation of damped coupled cluster response theory presented, up to CCSD level, by Kauczor et al., J. Chem. Phys., 2013, 139, 211102, and recently extended to the solution of the complex left response multipliers by Faber and Coriani, J. Chem. Theory Comput., 2019, 15, 520, has been modified to include a core–valence separation projection step in the iterative procedure. This allows one to overcome serious convergence issues that specifically manifest themselves at the CCSD level when addressing core-related spectroscopic effects using large basis sets. The spectra, obtained adopting the new scheme for X-ray absorption and circular dichroism, as well as resonant inelastic-X-ray scattering, are presented and discussed. Core–valence separated results for non-resonant X-ray emission are also reported.