Radiative-collisional generation of sound in gases by monopulse optical excitation

A theoretical investigation is made of the generation of sound in the field of a single light pulse caused by light-induced gas drift. The spectral characteristics of the acoustic signal and their relation to the parameters of the medium and of the radiation are analyzed. Two mechanisms of light-induced sound generation are established: a selective mechanism and a diffusion mechanism. It is found that the restrictions for the medium and the radiation are less stringent for the case of a diffusion mechanism. In this way the diffusion mechanism is more universal. The results of the analysis are recommended as a theoretical basis of a method for determining the transport scattering cross sections of excited atomic particles by using pulsed lasers and high-sensitivity optical acoustic spectroscopy.