Partition Function and Dissociation Energy for Sc2X5Σ−u

Abstract

An improved partition function for the Sc2 dimer including eight low-lying states has been computed at the multireference internally contracted ACPF level using large, generally contracted basis sets. The experimental third-law value for the dissociation energy is recomputed using the new dimer partition function giving an experimental dissociation energy of 1.05 eV, a reduction by 0.07 eV compared with the earlier experimental value. The computed spectrum is very strongly affected by dynamical correlation so that lower-level theoretical approaches such as CASSCF are shown to give unreliable results.