Polarization effects in metastable neon atom (Ne* (3P2)) on ground state neon atom collision at thermal energy

The difference Δ between the differential cross section for Ne*(3P2atoms polarized either in state ǀj=2, m=+2 > or ǀj=2,m=−2 >, colliding at thermal energy with a groundstate target (Ne,O2), is measured. In the symmetric case Ne*-Ne, direct and exchange contribution are observed. General properties of Δ, derived from symmetry considerations, are established; in particular: (i) the interference character of Δ, (ii) the role played by the azimuthal dependence of the scattering amplitudes, (iii) the property Δ(0) = Δ(180°)=0. The relationship between the Fourier harmonics introduced in this discussion and the scattering amplitudes used in standard collision treatments are given.