Intensity of ultrasound excited in stimulated light scattering by optically-controlled chemical reactions

Equations are obtained for the ultrasound intensity and for the number of phonons per scattered light quantum in stimulated scattering in thermodynamically nonequilibrium media when the rates of chemical reactions depend on the optical intensity. Estimates show that in gas mixtures such as CO₂ and n-C₃F₇I at a total pressure of 0.5 atm, in which exothermic reactions between iodine atoms and organofluoric radicals occur as a result of photolysis of n-C₃F₇I, light having an intensity of ~10⁵ W/cm², resonantly interacting with iodine atoms, can excite ultrasound having an intensity of tenths of a watt per square centimeter at a frequency of ~1 MHz. In this case, ~10⁴ phonons are produced per scattered photon.