PHOTODISSOCIATION OF I-2(-)(AR)(N) CLUSTERS STUDIED WITH ANION FEMTOSECOND PHOTOELECTRON-SPECTROSCOPY

Anion femtosecond photoelectron spectroscopy was used to follow the dy namics of the I-2(-)(Ar)(6) and I-2(-)(Ar)(20) clusters subsequent to photodissociation of the I-2(-) chromophore. The experiments showed th at 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 t hat attractive interactions between the departing anion fragment and t he solvent atoms persisted for 1200 femtoseconds. Photodissociation of I-2(-)(Ar)(20) results in caging of the I-2(-) followed by recombinat ion 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 process es are complete in 35 and 200 picoseconds, respectively.