Transition-Potential Coupled Cluster

Abstract

The problem of orbital relaxation in computational core-hole spectroscopies, including x-ray absorption and x-ray photoionization, has long plagued linear response approaches, including equation-of-motion coupled cluster with singles and doubles (EOM-CCSD). Instead of addressing this problem by including additional electron correlation, we propose an explicit treatment of orbital relaxation via the use of "transition potential" reference orbitals, leading to a transition-potential coupled cluster (TP-CC) family of methods. One member of this family in particular, TP-CCSD(1/2), is found to essentially eliminate the orbital relaxation error and achieve the same level of accuracy for core-hole spectra as is typically expected of EOM-CCSD in the valence region. These results show that very accurate x-ray absorption spectra for molecules with first-row atoms can be computed at a cost essentially the same as that for EOM-CCSD.

25 pages, 5 figures, 1 table

References in corpus (2)

• Highly Accurate Prediction of Core Spectra of Molecules at Density Functional Theory Cost: Attaining sub eV Error from a Restricted Open-Shell Kohn-Sham Approach
• Efficient Simulation of Near-Edge X-ray Absorption Fine Structure (NEXAFS) in Density-Functional Theory: Comparison of Core-Level Constraining Approaches

Cited by in corpus (8)

• Accurate core excitation and ionization energies from a state-specific coupled-cluster singles and doubles approach
• Accurate core-excited states via inclusion of core triple excitations in similarity-transformed EOM theory
• A benchmark study of core-excited states of organic molecules computed with the generalized active space driven similarity renormalization group
• Generalization of one-center non orthogonal configuration interaction singles to open shell singlet reference states: Theory and application to valence-core pump-probe states in acetylacetone
• Transition-Potential Coupled Cluster II: Optimization of the Core Orbital Occupation Number
• Theoretical Investigation of The X-Ray Stark Effect in Small Molecules
• Explicit core-hole single-particle methods for L- and M- edge X-ray absorption and electron energy-loss spectra
• Transition moments for STEOM-CCSD with core triples