Bilinear Orbital Expansion of Geminalhyphen;Product Correlated Wavefunctions

摘要

Bilinear orbital expansions of geminals are proposed for use in forming a total electronic wavefunction from a single antisymmetrized product of geminals. This gives rise to a more general analytical form for the wavefunction than that represented by the previously discussed interacting, separated, or identical geminal models. Variational determinations of the geminals are enhanced by this more general scheme although additional algebraic complexities arise as well. Explicit expressions are given for the geminal expansions, density matrices, energy, and variational equations in the case of two singlet pairs of electrons.