The helium-hydrogen fluoride differential scattering cross-section

The total differential scattering cross-section for He/HF has been measured at two collision energies. Several potential energy surfaces have been used to analyse the data, with particular attention being given to anisotropic models based on Hartree-Fock calculations. Coupled states, IOS and single channel spherical potential methods are used to predict the cross sections from the potential surfaces. It is shown that the spherical part of the potential dominates thermal scattering events and is characterised by the following parameters: zero crossing σ = 0·278 ± 0·003 nm; position of minimum R m = 0·311 ± 0·003 nm; and well depth ϵ = 34·5 ± 2·5 K.