Transposition of the Theories Describing Superconducting Systems to Molecular Systems. Method of Biorbitals

A new theory of the electronic structure of molecules is proposed, based on a wavefunction of the following type: φSCF−BI=NAψ(1,2)ψ(3,4)···ψ(2N···1,2N).This wavefunction is called the self-consistent-field biorbital wavefunction, and the factors ψ(i, j) are called biorbitals. This function is discussed, the corresponding energy expression is derived, and the variational equations leading to the best possible φSCF–BI are presented. This theory is the molecular version of Blatt's theory of superconducting systems.