Unimol. reactions induced by absorption of multiple quanta of monochromatic IR radiation were studied on a model system comprising dissocn. of CF2HCl giving CF2 and HCl. Three expts. providing detailed information of IR multiphoton chem. were performed which included measurements of the time dependence of the abs. reaction yield during and after the laser pulse, detn. of the av. no. of photons absorbed per mol. of CF2HCl, and measurement of the total reaction yield in strong elec. and magnetic fields.