SpinFree SelfConsistentField Theory
Abstract
HartreeFock (HF) equations are derived for an Nelectron system with a spinfree Hamiltonian. All eigenstates of S^{2} are considered for both open and closedshell states. States which possess two or more spincoupling schemes (structures) are treated by mixedstructure kets. A procedure to optimize the mixture of structures is incorporated into the HF equations. A certain mixedstructure ket called the immanant is defined and used to derive the HF equations for a spinprojected Slater determinant. The conventional equations for single determinants and doubly occupied orbitals are derived as special cases. The spinfree method is used throughout: Permutational symmetry of a spinfree ket establishes the corresponding spin eigenvalue.
 Publication:

Physical Review
 Pub Date:
 March 1968
 DOI:
 10.1103/PhysRev.167.139
 Bibcode:
 1968PhRv..167..139P