Laser induced excitation of ammonia at 1076 cm^-1 in the megawatt region

Absorption of high-power CO₂-laser radiation by 5-244 Torr of ammonia has been studied. The incident infrared radiation energy was varied in the range 0.04-0.70 Jcm^-2 pulse^-1 corresponding to average power levels of 0.2-3.5 MW cm^-2, respectively. It is shown that experimental measurements can conveniently be summarized using an empirical absorption law, which is a modified Lambert-Beer law, written in terms of fluences or doses. A kinetic model is analyzed in relation to the data thus presented. © 1979 American Institute of Physics.