Heterogeneous and hyperfine interactions between valence states of molecular iodine correlating with the I(2P1/2) + I(2P1/2) dissociation limit

Detailed analysis of interactions between all 0(g)(+), 1(u), and 0(u)(-) weakly bound states of iodine molecule correlating with the I(P-2(1/2)) + I(P-2(1/2)) (bb) dissociation limit has been performed. For this purpose, the 0(u)(-) (bb) state has been described using analysis of rotationally resolved excitation spectra of luminescence from the g0(g)(-) state populated in a three-step three-color perturbation facilitated excitation scheme via the 0(u)(-) state. Energies of 41 rovibrational levels, molecular constants, and potential energy curve have been determined. Energy gaps between closest rovibrational levels of the 0(u)(-) and 0(g)(+), 1(u) (bb) states are found to be large, similar to 6 cm(-1). However, interaction of all three 0(g)(+), 1u, and 0-u (bb) states has been observed. It has been found that the 0(u)(-) and 1(u) electronic states are mixed by heterogeneous interactions, while their mixing with the 0(g)(+) one is due to hyperfine interactions predominantly. Admixture coefficients and electronic matrix elements of the coupling between the 0(g)(+) similar to 1(u), 0(g)(+) similar to 0(u)(-), and 0(u)(-) similar to 1(u) states have been estimated. Published by AIP Publishing.