Classical approximation in the theory of ultraviolet dissociation of molecules

A classical one-dimensional model of ultraviolet dissociation of molecules of iodides suitable for lasing is developed allowing for the anharmonicity of the vibrations, "bending" of the term representing an electronically excited state, change in the electron matrix element, and possible deviations of the vibrational distributions of the dissociating molecules from equilibrium. A detailed analysis is made of the ultraviolet dissociation spectra of the CF₃I molecules for which all the characteristic parameters are deduced. This model is in quantitative agreement with the experimental results obtained in a wide range of wavelengths (λ = 275–450 nm). The feasibility of ultraviolet absorption probing of vibrational distributions is demonstrated by considering the example of the spectra of the CF₃I molecules interacting with the radiation field of a CO₂ laser.