Non-adiabatic coupling as friction in the formation of H3+: A classical mechanical study

Abstract

By going beyond the Born-Oppenheimer approximation and treating the non-adiabatic coupling terms (NACTs) as equivalent to a frictional force in a molecular system, the classical equations of motion are solved for a test case of H3+. Using an ab initio potential energy surface for the ground electronic state and its NACTs with the first excited state of H3+, it is shown that (D+, H2) collisions are slowed enough to result in trapping and formation of a stable DH2+.