The interaction of atomic and molecular nitrogen with argon by scattering measurements

Abstract

Absolute integral cross sections for collisions of N₂ molecules and N atoms with Ar are measured as a function of velocity at thermal energies. For the N₂–Ar case the glory structure observed in the cross section vs velocity plot does not appear to be affected by the anisotropy of the interaction. An analysis in terms of a spherically averaged potential model can be performed thus obtaining a reliable potential function. The N–Ar cross sections presented here are the first collisional study of N atoms leading to significant information on the interaction potential. Although, as shown by the magnetic behavior, the N atom beam is essentially a mixture of atoms in the two metastable ²D_J and ²P_J states, the results obtained, together with other properties of the excited atoms, indicate the presence of a low anisotropy in the N–Ar interaction. An analysis in terms of a simple and yet realistic potential model has been performed obtaining meaningful potential parameters for the N–Ar system. The results for N–Ar are tentatively inserted in a comparison of trends and regularities of the interactions of some second row elements of the periodic table with Ar.