Investigation of dissociative photoionization pathways for orientation-selected molecules by phase-controlled laser fields

Intense (5.0 × 1012 W/cm2) nanosecond phase-controlled laser fields consisting of fundamental and second-harmonic light induce orientation-selective molecular tunneling ionization in a randomly orientated molecular ensemble in a gas phase. The selection of oriented molecules enables one to elucidate dissociative photoionization pathways while eliminating loss of information due to orientational averaging. Here, we have investigated the dissociative ionization of hydrofluorocarbon molecules induced by phase-controlled two-color laser fields. From the phase-dependent behavior of photofragment emission from orientation-selected molecules, dissociation pathways were elucidated experimentally. Bond dissociation energies obtained by quantum chemical calculations support the identified dissociation pathways.