Trapping and migration of P-state atoms in rare gas solids: effect of angular momentum anisotropy for model O(P-3) and C(P-3) atoms

Classical simulations of model O(P-3) atom isolated in Ar, Kr and Xe crystals with the variable magnitude and sign of the angular momentum anisotropy are performed. The guest-host interaction anisotropy remarkably affects the structure of the atomic trapping sites and the barriers to the temperature-induced atomic mobility. For interstitial trapping, inversion of anisotropy induces a kind of critical phenomenon, which transforms the migration path saddle point to a minimum and another saddle. As a result, a new peculiar axially symmetric interstitial site is formed with the migration barrier reduced. Preliminary ab initio-based study of the C(P-3) atom, whose interactions with Ar, Kr and Xe have the anisotropy opposite to oxygen, fully confirms the model analysis. Our results emphasise profound effect of the angular momentum anisotropy on the structure and dynamics of the open-shell atoms at matrix isolation. [GRAPHICS] .