Photophysics and photochemistry of I2 (D, D′) in rare gas clusters Original Research Article

We report the resolved fluorescence spectra of I2, clustered with Ar, Kr and Xe and excited at 193 nm to the D state of the first ion-pair manifold. In Ar and Kr clusters, a broad, featureless emission band is seen, which shifts to lower energies as the cluster size increases. In Xe clusters, this band is not observed; there is very efficient quenching of all emission. Under some expansion conditions, XeI∗ excimer emission is observed with a two-photon dependence on the intensity of the 193 nm excitation laser. These results are all explained by a model in which excitation of I2 into the ion-pair manifold is followed by a harpooning-type electron transfer and formation of an excited charge transfer complex between I2 and a rare gas atom.