Adequacy of the adiabatic description of rovibronic transitions in diatomic molecules: The isotope effect in probabilities of the d3Π-u, v', N→a3Σ+g, v double-prime,N transition in H2 and D2

To check the adequacy and develop the theoretical models used in a semiempirical determination of the probabilities of rovibronic transitions, it is proposed to carry out a comparative optimization analysis of experimental data on the relative probabilities and radiative lifetimes of two or more isotopes. A program package has been developed for a semiempirical determination of an entire matrix set of probabilities of vibronic radiative transitions that makes it possible to conduct a study of the adequacy of a theoretical model (adiabatic approximation and type of approximation of the electron moment as a function of internuclear distance M(r)n'ndouble-prime) and to check the stability and uniqueness of the solution of the inverse problem of semiempirical determination of Mn'ndouble-prime (r). For the first time the relative probabilities of d3Π-u, v', N→a3Σ+g, v double-prime, N of spontaneous emission of the D2 molecule have been measured, and new data on the same transitions in H2 have been obtained. It was found that the isotope effect in the probabilities of the indicated transitions of the hydrogen molecule is adequately described within the limits of experimental accuracy in the framework of the adiabatic approximation