Photodetachment, photofragmentation, and fragment autodetachment of [O 2n(H2 O) m] - Clusters: Core-anion structures and fragment energy partitioning

Abstract

Building on the past studies of the O 2n- and O 2- (H2 O) m cluster anion series, we assess the effect of the strong hydration interactions on the oxygen-core clusters using photoelectron imaging and photofragment mass spectroscopy of [O2n (H2 O) m]- (n=1-4, m=0-3) at 355 nm. The results show that both pure-oxygen and hydrated clusters with n≥2 form an O4- core anion, indicated in the past work on the pure-oxygen clusters. All clusters studied can be therefore described in terms of O4- (H2 O) m (O2) n-2 structures, although the O4- core may be strongly perturbed by hydration in some of these clusters. Fragmentation of these clusters yields predominantly O2- and O 2- (H2 O) l (l