Inversion of the populations of vibrational levels of anharmonic molecules under the influence of optical and thermal pulses

An investigation is made of nonequilibrium processes in a system of diatomic anharmonic molecules subjected to optical and thermal pulses. Numerical integration of a system of rate equations for the populations is used to study the evolution of the distribution function to its quasisteady state. Passage of a shock wave through a gas of such molecules establishes a new quasisteady state corresponding to the translational temperature behind the shock wave. The function describing the distribution of the populations between the vibrational levels passes through a series of forms corresponding to the establishment of an absolute inversion.