Unrestricted Hartree–Fock
SCF-MO METHOD FOR CALCULATING OPEN-SHELL SYSTEMS
Pople-Nesbet equations; Unrestricted Hartree-Fock
Unrestricted Hartree–Fock (UHF) theory is the most common molecular orbital method for open shell molecules where the number of electrons of each spin are not equal. While restricted Hartree–Fock theory uses a single molecular orbital twice, one multiplied by the α spin function and the other multiplied by the β spin function in the Slater determinant, unrestricted Hartree–Fock theory uses different molecular orbitals for the α and β electrons.