title: Photoelectron imaging study of the effect of monohydration on O2 - photodetachment.
abstract: The photodetachment of the O(2)(-).H(2)O cluster anion at 780 and 390 nm is investigated in comparison with O(2)(-) using photoelectron imaging spectroscopy. Despite the pronounced shift in the photoelectron spectra, the monohydration has little effect on the photoelectron angular distributions: for a given wavelength and electron kinetic energy (eKE) range, the O(2)(-).H(2)O angular distributions are quantitatively similar to those for bare O(2)(-). This observation confirms that the excess electron in O(2)(-).H(2)O retains the overall character of the 2ppi(g) HOMO of O(2)(-). The presence of H(2)O does not affect significantly the partial wave composition of the photodetached electrons at a given eKE. An exception is observed for slow electrons, where O(2)(-).H(2)O exhibits a faster rise in the photodetachment signal with increasing eKE, as compared to O(2)(-). The possible causes of this anomaly are (i) the long-range charge-dipole interaction between the departing electron and the neutral O(2).H(2)O skeleton affecting the slow-electron dynamics; and (ii) the s wave contributions to the photodetachment, which are dipole-forbidden for pi(g)(-1) transitions in O(2)(-), but formally allowed in O(2)(-).H(2)O due to lower symmetry of the cluster anion and the corresponding HOMO.
authors.affiliation: Department of Chemistry, University of Arizona, Tucson, AZ 85721-0041, USA.
authors.forename: F Ahu
authors.initials: FA
authors.lastname: Akin
authors.forename: Laura K
authors.initials: LK
authors.lastname: Schirra
authors.forename: Andrei
authors.initials: A
authors.lastname: Sanov
mesh_terms: D004583:Electrons; D008956:Models, Chemical; D008958:Models, Molecular; D010777:Photochemistry; D013057:Spectrum Analysis; D013481:Superoxides / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D013481:Superoxides