ROHF Theory Made Simple

摘要: Restricted open-shell Hartree-Fock (ROHF) theory is formulated as a projected self-consistent unrestricted HF (UHF) model by mathematically constraining spin density eigenvalues. The resulting constrained UHF (CUHF) wave function identical to that obtained from Roothaan's effective Fock operator. Our $\alpha$ and $\beta$ CUHF operators are parameter-free have canonical orbitals orbital energies physically meaningful in UHF, except for eliminating contamination. present approach removes ambiguities ROHF the non-uniqueness of methods build upon them. We benchmarks demonstrate physical correctness good agreement with experimental results.