Collisional quenching of molecular ro-vibrational energy by He buffer loading at ultralow energies

In the present review we summarize in some detail the ample theoretical literature which has discussed over the last few years the computational treatment of collisionally inelastic processes at ultralow temperatures. The analysis is centred on the ab initio quantum treatment of collisional quenching of ro-vibrational states of simple diatomics, neutral and ionic, polar and homonuclear, interacting with a helium buffer gas. Several specific examples are analysed and their features are linked with both the details of their interaction potential energy surfaces and the special behavior of ultralow energy quantum dynamics.