Light-Induced Molecular Potentials

We investigate the dissociation dynamics of molecules exposed to intense laser fields that induce electronic Rabi frequencies comparable to the frequency of nuclear vibration. A fast, mass selected beam of the simply structured model molecule Ar{sub 2}{sup +} was prepared in low vibrational levels and crossed with a dye laser beam (532nm, {le}5{times}10{sup 12}W/cm{sup 2}). The absolute number of photofragments has been measured as a function of intensity. A clear experimental signature of light-induced potential curves is observed: enhanced dissociation by tunneling through a light-induced potential barrier. This is deduced from a quantitative comparison with theoretical predictions. {copyright} {ital 1997} {ital The American Physical Society}