Use of semifloating orbitals in molecular calculations

The use of semifloating orbitals of type A + cA', where A is an orbital centered on nucleus a and A' is a floating orbital, in quantum chemical calculations was proposed. The bonding wave function of diatomic molecule, which was constructed on the basis of semifloating orbitals by means of the electron pairs method, has a configuration of type A'(1)B(2) + B(1)A'(2) + A(1)B'(2) + B'(1)A(2); this configuration can be called semifloating two-electron function. In the example of a variation calculation of the hydrogen molecule it was shown that the use of semifloating functions together with the traditionally used functions fixed on the nuclei and pure floating functions decreases the calculated molecular energy and refines considerably the electron density distribution along the molecular axis.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 6, pp. 712–715, November–December 1986.