Geometric Direct Minimization for Low-Spin Restricted Open-Shell Hartree-Fock Theory.

ABSTRACT: It has recently been shown that configuration state functions (CSFs) with local orbitals can provide a compact reference state for low-spin open-shell electronic structures, such as antiferromagnetic states. However, optimizing a low-spin configuration using self-consistent field (SCF) theory has been a long-standing challenge since each orbital must be an eigenfunction of a different Fock operator. We introduce a low-spin restricted open-shell Hartree-Fock (ROHF) algorithm to optimize any CSF at mean-field cost. This algorithm employs quasi-Newton Riemannian optimization on the orbital constraint manifold to provide robust convergence, extending the geometric direct minimization approach to open-shell electronic structures with arbitrary genealogical spin coupling. Numerical calculations

SUBMITTER: Burton HGA 

PROVIDER: S-EPMC12529922 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature