A unified molecular force field via a model theory of isoelectronic diatomic molecules

Abstract

Electronic energy curves for diatomic molecules come in a wide variety of shapes. More categorically, these correspond to stable, metastable or repulsive states. We propose that a great deal of this apparently diverse behavior might in fact be contained in a single isoelectronic energy surface E(R,Z,Z′). That is, each kind of curve can be thought of as a particular cross section of the surface corresponding to some range of the nuclear charges Z and Z′. Analytic representations for these surfaces have been given and their properties examined. We have found that they are folded and contain critical points. These features put limits on the number of isoelectronic species that can exist in a sequence and interconnect their properties. By this we understand that data gathered on even the repulsive states of one molecule of an isoelectronic sequence contains information about the stable and metastable members of that sequence.