Optical transitions in excited alkali + rare-gas collision molecules and related interatomic potentials:

Abstract

A comparison is made of experimental far-wing profiles for the system with quantum calculations of thermally averaged free - free continua. Using input adiabatic potentials and transition moment functions from both ab initio and semi-empirical approaches, the comparison shows: (i) new ab initio potentials for reproduce the spectral positions of the observed rainbow satellites well; the height of the barrier predicted agrees with experiment to within , whereas its position is too large by ; (ii) potentials obtained with various semi-empirical methods reproduce the satellite structure qualitatively, but are generally too repulsive in the state at intermediate and large internuclear separations; (iii) transition moment functions for the asymptotically forbidden transitions reproduce, with different degrees of accuracy, the intensity of the red-wing satellite related to the potential extremum around . The vibrational energies in the and states calculated with the ab initio potentials reproduce to within a few those obtained from rotationally resolved band spectra reported in the literature.