Hydrogen bonding rn microsolvation: photoelectron imaging and theoretical studies on Au_x~--(H2O)_n and Au_x~--(CH3OH)_n (x = 1, 2; n = 1, 2) complexes

摘要

We have combined photoelectron velocity-map imaging (VMI) spectroscopy and theoretical calculations to elucidate the geometry and energy properties of Au_x~-(Solv)_n clusters with x = 1, 2; n = 1, 2; and Solv = H2O and CH3OH. Besides the blue-shifted vertical electron detachment energies (VDEs) of the complexes Au_(1.2)~-(Solv)_n with the increase of the solvation number (n), we independently probed two distinct Au~-(CH3OH)_2 isomers, which combined with MP2/aug-cc-pVTZ(pp) calculations represent a competition between O...H-O hydrogen bonds (HBs) and Au...H-O nonconventional hydrogen bonds (NHBs). Complementary calculations provide the total binding energies of the low-energy isomers. Moreover, the relationship between the total binding energies and total VDE_(shift) is discussed. We found that the Au_(1.2)~- anions exhibit halide-analogous behavior in microsolvation. These findings also demonstrate that photoelectron velocity map imaging spectroscopy with the aid of the ab initio calculations is an effective tool for investigating weak-interaction complexes.