Solvation effects on angular distributions in H-(NH _3)_n and NH_2~-(NH_3) _n photodetachment: Role of solute electronic structure

摘要

We report 355 and 532 nm photoelectron imaging results for H ~-(NH_3)_n and NH_2~-(NH _3)_n, n=0-5. The photoelectron spectra are consistent with the electrostatic picture of a charged solute (H~- or NH _2~-) solvated by n ammonia molecules. For a given number of solvent molecules, the NH_2~- core anion is stabilized more strongly than H~-, yet the photoelectron angular distributions for solvated H~- deviate more strongly from the unsolvated limit than those for solvated NH2-. Hence, we conclude that solvation effects on photoelectron angular distributions are dependent on the electronic structure of the anion, i.e., the type of the initial orbital of the photodetached electron, rather than merely the strength of solvation interactions. We also find evidence of photofragmentation and autodetachment of NH_2~-(NH_3)_(2-5), as well as autodetachment of H~-(NH_3)_5, upon 532 nm excitation of these species.