Resonant optical excitation of the I2 ion-pair states through the RgI2 complexes in the valence states correlating to the 2P1/2 + 2P1/2 limit

The luminescence spectra of I2(β1g,νβ ⩽ 59 and D 0 u + , νD ⩽ 61) ion-pair states are observed in I2 + Rg mixtures after irradiation by Nd:YAG (1064.48 and 532.24 nm) laser beams. Luminescence excitation is attributed to two-step 1064.48 + 532.24 nm pumping of RgI2 complexes in 0 g + and 1u valence states correlating to third valence dissociation limit 2P1/2 + 2P1/2. Subsequent decay of the complexes gives free I 2 ( 1 u , 0 g + ) molecules, which are excited to the β1g and D 0 u + states by third 532.24 nm photon. This mechanism conforms all experimental findings and provides the first indication for optical population of the RgI2 complexes in the valence states different from the B 0 u + and X 0 g + .