Nonlinear optics of the stratosphere and the laser chemistry of ozone

Experimental results are presented on nonlinear effects disclosed in the sounding of the stratosphere by ultraviolet radiation, and on the infrared laser chemistry of ozone. It is shown that only the first vibrational level of the nu3 mode is excited with a q-factor not higher than 0.2 at relatively low intensities of radiation (of the order of units of MW/sq cm) and ozone pressures of 0.1-10 torr. The energy relaxation process in this case occurs primarily between the lower vibrational levels of O3 molecules, and the model of lower vibrational levels can be applied to this process. At higher intensities (up to GW/sq cm), a significant increase in the number of photons absorbed by one molecule of ozone occurs; this leads to cascade excitation of the vibrational levels of ozone with K not less than 2. In this case, the upper vibrational levels play a significant role in energy relaxation, and intense heating and nonequilibrium dissociation of O3 gas can occur; the dissociation model of ozone can be used to describe these processes.