Ar*(3p5 4s, 3P0,2) on Ar(3p6, 1S0) collisions at thermal energies

Abstract

Elastic differential cross sections for Ar*(3p5 4s, 3P 0,2) on Ar(3p6,1S0) collisions have been measured in the thermal energy range (40-180 meV), using a time-of-flight technique in a crossed beam experiment. These results are calibrated by reference to the total cross section, obtained in absolute value by measuring at the same time the UV argon line attenuation by argon. Experimental cross sections are compared to those calculated from ab initio potentials, by a semi-quantal method By using particular scattering directions, where the time-of-flight spectra exhibit unusual properties, the dominant elastic contribution has been strongly reduced and inelastic. differential cross sections for the exothermal fine structure transition, 3p0 → 3P2 + 175 meV, have been measured in relative values. Some defects in g-state potentials at short internuclear distances — which already appeared in the discussion about the elastic process —, are discussed