PNNL

Abstract

We use a Mg+ metal to extend the size regime of water clusters to extrapolate to the bulk limit of the Vertical Detachment Energy (VDE) of the solvated electron to >3,200, a value between one to over two orders of magnitude for clusters previously measured experimentally or computed theoretically. We relate the VDE to the energy difference between the Mg+(H2O)n and Mg2+(H2O)n systems and the metal’s second ionization potential. The extrapolated bulk VDEs of the localized surface electron, which moves away from the metal as n increases, are 1.89±0.01 eV for semiempirical (n~3,200; PM6-D3H4) and 1.73±0.03 eV (n~150; HF), 1.83±0.02 eV (n~150; MP2) for ab-initio, in excellent agreement with the 1.6 – 1.8 eV range of experimental results. The VDEs converge from above (larger values) to the bulk limit, in a manner qualitatively different than previous studies and experiments, a fact justifying the “back door” approach to the solvated electron.