Interatomic potentials for the Hg-Xe system from measurements of the temperature-dependent absorption spectrum

Abstract

The absorption profile and the temperature dependence of the Hg resonance line at 253.7 nm perturbed by Xe at a density of about 1*10 19 atoms/cm 3 have been carefully studied with a high-resolution double beam spectrometer. Interatomic potentials for Hg-Xe in the ground electronic state 1 O + as well as the excited state 3 O + in a wide range of separations (from a repulsive wall up to the van der Waals attraction region) have been deduced from the spectrum. Some important results for the excited 3 1 state, in particular the van der Waals coefficient C 6 , are also obtained. The ground-state potential with well parameters of epsilon =240+or-10 cm -1 and R m =4.10+or-0.03 AA, derived experimentally without recourse to any external data, is well reproduced by the Maitland-Smith (1973) ( epsilon , R m , alpha , beta ) function for alpha =11 and beta =17. The well depth for the 3 O + excimer state is found to be 1450+or-100 cm -1 at a separation of 3 AA. The 1 O + to 3 O + transition moment in the range of separations considered seems to be independent of R.