ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
We report the 790 nm photofragmentation of mass-selected I−2⋅Arn clusters, n=1 to 27. We determine the I−+I caging efficiency as a function of the number of solvent Ar atoms and compare these results with I−2 in CO2 clusters. Caging is much less effective with Ar. In addition to "normal'' caged photoproducts (I−2⋅Arm, where m〈n), the evaporation process following photoexcitation produces "solvent-separated'' (I−...I)⋅Arm photofragments, where the I−2 bond has not reformed. These metastable species comprise ∼55% of the photofragment yield for precursor clusters for n≥14 and have lifetimes (approximately-greater-than)5 μs. This unusual photofragment exists either as a trapped excited electronic state or as a solvent-separated pair at an internuclear separation of ∼5.5 A(ring). The photofragmentation data also exhibit the existence of two distinct isomeric forms of the precursor I−2⋅Arn, for n≤14. These forms are evaporatively distinct in that one isomer displays highly nonstatistical fragmentation, probably arising from a cluster in which the I−2 resides on the surface, rather than in the interior. The photofragmentation distribution of the other form exhibits statistical behavior, consistent with the evaporation of an I−2 solvated inside the cluster. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.472098
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