Photodissociation of I-2(-)(Ar)(n) clusters studied with anion femtosecond photoelectron spectroscopy

Anion femtosecond photoelectron spectroscopy was used to follow the dynamics of the I-2(-)(Ar)(6) and I-2(-)(Ar)(20) clusters subsequent to photodissociation of the I-2(-) chromophore. The experiments showed that photodissociation of the I-2(-) moiety in I-2(-)(Ar)(6) is complete by approximately 200 femtoseconds, just as in bare I-2(-), but also that attractive interactions between the departing anion fragment and the solvent atoms persisted for 1200 femtoseconds. Photodissociation of I-2(-)(Ar)(20) results in caging of the I-2(-) followed by recombination and vibrational relaxation on the excited (A) over tilde (2) Pi(g,3/2) and the ground (X) over tilde 2 Sigma(u)(+) states; these processes are complete in 35 and 200 picoseconds, respectively.