On the use of dipole moment as a collective coordinate in constrained variational calculations

Abstract

The dipole moment function of a diatomic molecule may be viewed as a continuous collective coordinate which encodes a lot of information about sharing of electrons between the atoms concerned. By its very nature it takes cognizance of certain many-body effects and should shape the constrained wavefunction or the one electron density in much the same way as would explicit inclusion of the same many-body effects. A case study of the problem with lithium hydride as the model system has been presented and the long range behaviour of the constrained density analysed. The spectrum of the constrained Fock operator is compared with that of the unconstrained one.