Communications: Observation of two classes of isomers of hydrated electrons in sodium-water clusters

Abstract

A new class of sodium-water clusters with a low lying ionization potential (IP) is characterized by their photoionization spectra in molecular beam experiments. This implies that Na (H2 O) n clusters coexist for n15 in two forms of significant abundances being distinguished by their IPs of ∼2.8 and ∼3.2 eV. A tentative quantum chemical characterization was achieved by simulating ionization spectra for selected cluster sizes using an ab initio molecular dynamics approach. Experiment and theory suggest that the Na+ -e- distance is significantly larger in the clusters with the lower IP. This indicates that the solvated electron in Na (H2 O) n clusters very probably forms with the Na+ counterion both a solvent separated and a contact ion pair. © 2010 American Institute of Physics.