Core-Excited States for Open-Shell Systems in Similarity-Transformed 
Equation-of-Motion Theory

Casanova-Páez, Marcos; Neese, Frank

doi:10.1021/acs.jctc.4c01181

Item

ITEM ACTIONSEXPORT

Add to Basket

Local TagsRelease HistoryDetailsSummary

Released

Journal Article

Core-Excited States for Open-Shell Systems in Similarity-Transformed Equation-of-Motion Theory

MPS-Authors

/persons/resource/persons302603

Casanova-Páez, Marcos
Research Department Neese, Max-Planck-Institut für Kohlenforschung, Max Planck Society;

/persons/resource/persons216825

Neese, Frank
Research Department Neese, Max-Planck-Institut für Kohlenforschung, Max Planck Society;

External Resource

No external resources are shared

Fulltext (restricted access)

There are currently no full texts shared for your IP range.

Fulltext (public)

There are no public fulltexts stored in PuRe

Supplementary Material (public)

There is no public supplementary material available

Citation

Casanova-Páez, M., & Neese, F. (2025). Core-Excited States for Open-Shell Systems in Similarity-Transformed Equation-of-Motion Theory. Journal of Chemical Theory and Computation, 21(3), 1306-1321. doi:10.1021/acs.jctc.4c01181.

Cite as: https://hdl.handle.net/21.11116/0000-0010-E6E0-D

Abstract

X-ray absorption spectroscopy (XAS) is a powerful method for exploring molecular electronic structure by exciting core electrons into higher unoccupied molecular orbitals. In this study, we present the first integration of the spin-unrestricted similarity-transformed equation-of-motion coupled cluster method (CVS-USTEOM-CCSD) for core-excited and core-ionized states into the ORCA quantum chemistry package. Using the core–valence separation (CVS) approach, we evaluate the accuracy of CVS-USTEOM-CCSD across 13 open-shell organic systems, covering over 20 core excitations with diverse spin multiplicities (doublet, triplet, and quartet). The implementation leverages automated active space selection, incorporating CIS natural orbitals to efficiently capture electronic transitions. We benchmark the predicted K- and L-edge spectra against experimental data, underscoring the accuracy of the CVS-USTEOM-CCSD method for high-precision core excitation studies.