Perturbations of radiative lifetimes of rovibrational levels of the I1Πg- and J1Δg- states of H2

Adiabatic and nonadiabatic values of radiative lifetimes of rovibrational levels of the electronic states I(1)Pi(g)(-) and J(1)Delta(g) of the H-2 molecule are calculated by using data of ab initio calculations of matrix elements of dipole moments of transitions on vibrational wave functions. In comparing our results to those of semiempirical determination of these quantities that we obtained earlier, the two sets on average differed by 25% for rovibronic levels of the I(1)Pi(g)(-) state and by 30% for rovibronic levels of the J(1)Delta(g)(-) state. The inclusion of electronic-rotational interaction is shown to result in surprisingly small (<10%) variations of radiative lifetimes in spite of the considerable perturbations of probabilities of rovibronic transitions of the system of bands I(1)Pi(g)(-), J(1)Delta(g)(-) --> B(1)Sigma(u)(+), C(1)Pi(u)(+/-). Thus, strong mutual perturbations of the upper levels lead only to the redistribution of flows of various channels of spontaneous decay and do not considerably vary the total decay rate of these levels. (C) 2000 MAIK "Nauka/Interperiodica".