Reducedab initio theoretical internuclear potentials of diatomic molecules

Abstract

Ab initio theoretical ground state potentials of diatomic molecules calculated with the use of the variational CI-MO (configuration interaction method based on molecular orbitals) are analyzed with the use of the RPC (reduced potential curve) method. It is shown on a series of examples that the following statement is true even for inaccurateab initio calculations: in reduced form, the theoretical potential coincides to a high degree of accuracy with the reduced RKR (Rydberg-Klein-Rees) potential calculated from the spectroscopic data. Thus, with the use of the RPC method, even inaccurateab initio calculations (in particular for heavier molecules) may be used for the construction of rather accurate internuclear potentials and hence obtain a practical significance. The statement also holds for excited states if strong perturbations are not present.