Optical Population of Iodine Molecule Ion-Pair States via MI2 vdW Complexes, M = I2, Xe, of Valence States Correlating with the Third, I(2P1/2) + I(2P1/2), Dissociation Limit

The first results of measurements and analysis of excitation spectra of the lambda(lum) = 3250 angstrom luminescence corresponding to I-2(D0(u)(+) -> X0(g)(+)) transition as well as luminescence at lambda(lum) = 3400 angstrom, where I-2(D'2(g) -> A'2(u) and/or beta 1(g) -> A1(u)) transitions occur, observed after three-step, lambda(1) + lambda(f) + lambda(1), lambda(1) = 5321 - 5508.2 angstrom, lambda(f) = 10644.0 angstrom, laser excitation of pure iodine vapour and I-2 + Xe mixtures at room temperature via MI2 vdW complexes, M = I-2, Xe, of the I-2(0(g)(+), 1(u)(bb)) valence states correlating with the third, I(P-2(1/2)) + I(P-2(1/2)) (I-2(bb)), dissociation limit are presented. Luminescence spectra in the lambda(lum) = 2200-3500 angstrom spectral range are also analyzed. Strong luminescence from the I-2(D) and, probably, I-2(D' and beta) states is observed. We discuss three alternative mechanisms of optical population of the IP state. In our opinion, the mechanism including the MI2 complexes is the most probable.