Ar+2 molecules in intense laser fields

We have studied the interaction between intense laser fields (⩽ 7 × 1012 W/cm2) and molecules. For the diatomic molecular ion Ar+2 the number of photofragments as a function of laser intensity can be quantitatively explained in terms of light-induced adiabatic molecular potentials. The effects predicted by this model tend to cancel under realistic experimental conditions with a thermal distribution of the rovibrational populations. This molecular beam experiment allows for a fully quantitative comparison with theory, since only one dissociation channel is operative and all parameters relevant for a computational simulation have been determined.