General-order open-shell coupled-cluster method with partial spin adaptation I: formulations
Chemical Physics
2024-03-18 v1
Abstract
A general-order open-shell coupled-cluster method based on spatial orbitals is formulated. The method is an extension of the partial-spin adaptation (PSA) scheme from Janssen and Schaefer (Theor. Chim. Acta, 79, 1-42, 1991). By increasing the order of excitation operator and spin adaptation, the full configuration interaction (CI) limit is expected to be achieved. In the meanwhile, the advantages of spin-free approach in closed-shell systems: fourth-order truncation of the Baker-Campbell-Hausdorff (BCH) expansion and only -type connected terms are conserved.
Cite
@article{arxiv.2403.10128,
title = {General-order open-shell coupled-cluster method with partial spin adaptation I: formulations},
author = {Cong Wang},
journal= {arXiv preprint arXiv:2403.10128},
year = {2024}
}