Ab initio Morse/long-range potential energy functions plus spectroscopic and thermophysical properties of heteronuclear diatomic complexes of xenon with the rare gases

Abstract

New interatomic potential energy curves of xenon-helium (Xe-He), xenon-neon (Xe-Ne), and xenon-argon (Xe-Ar) atom pairs are developed by state-of-the-art ab initio calculations. Coupled cluster theory with single, double, and perturbative triple excitations [CCSD(T)] is used to calculate the majority of the interaction between atoms, on (multiple) augmented correlation-consistent basis sets for valence orbitals, extrapolated to the complete basis set (CBS) limit. Contributions from inner nuclear electronic correlation, relativistic effects, and higher-order excitations beyond CCSD(T) are also considered as corrections. For each system, an analytical Morse/long-range (MLR) potential functions, is fitted to 32 ab initio data using only 13 parameters: the poorest-quality fit yielded a dimensionless-root-mean-square-deviation (dd¯) of only 1.51. The ro-vibrational energy levels and wave functions, resonance states, effective radial potential energy curves, absorption spectra and thermophysical properties have also been computed.