Debate over the structure of the aqueous electron, long thought to be a settled matter, has been revived in recent years by the demonstration that certain spectroscopic features attributed to this species are successfully reproduced by a model that does not carve out an excluded volume in the structure of liquid water, as in the “canonical" structure model. One important example is the resonance Raman spectrum of e-(aq), which is significantly red-shifted and broadened relative to the Raman spectrum of neat liquid water. In simulations based on one-electron pseudopotential models, these features are reproduced by non-cavity-forming models but not with the canonical, cavity-forming model. This has fueled the debate over whether the structure really is a settled question. We investigate this issue using all-electron quantum chemistry calculations to compute the resonance Raman spectrum of e-(aq) and related systems including Cl-(aq). Notably, both systems reproduce the gross features attributed to the solvated electron, indicating that resonance Raman spectroscopy may be unable to distinguish between cavity-forming and non-cavity models of this species. In preliminary work, we have also used our new ab initio implementation of resonance Raman spectroscopy to simulate femtosecond stimulated Raman spectroscopy (FSRS) spectra for a variety of chromophores.

Ab Initio calculations of the resonance Raman spectrum of the hydrated electron

2019 Spring National Meeting

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