Interpretation of Alkali–Inert Gas Beam Scattering with the Buckingham–Corner Potential

Abstract

We have shown that recent measurements of alkali–inert gas beam scattering cross sections can be fit by a four parameter Buckingham–Corner potential with the same accuracy as with previously proposed four to seven parameter models. The Buckingham–Corner model contains a single Born–Mayer repulsive term and two attractive terms, the ordinary Van der Waals attraction and the second term in the London dispersion series. This model gives the correct broadening of the potential well. In addition some of the terms can be calculated theoretically. A fit of the measured total and differential cross sections for the systems Na–Xe and Na–Kr yields a set of form parameters which we assume to be characteristic of the alkali–inert gas interaction. Using these one can deduce well parameter values for each particular combination. Since the fit of the Buckingham–Corner potential is determined from the oscillatory structure of thermal beam measurements, its validity is confirmed only in the attractive region. A possible application of the model to the inert gas–inert gas interaction is discussed.