Comment on “Is the Hydrated Electron Vertical Detachment Genuinely Bimodal?”

Abstract

In a recent article [1], David Bartels addresses the issue of the band shape of the genuine binding energy spectrum of the hydrated electron. He essentially claims that the genuine binding energy of the hydrated electron must be Gaussian in shape independent of the photon energy used for ionization (hν), contrary to what was found in ref.[2] for excitations energies in the UV (hν = 3.6-5.8 eV). Further, he alleges that the "bimodal distribution" found for the genuine binding energy in ref.[2] must have resulted from deficiencies in the scattering cross sections used in the scattering calculations. Bartels concludes that these deficiencies arise from an allegedly wrong value of V0 = -1.0eV for the escape barrier used in the original fitting procedure to determine the scattering cross section. In the following, we show that these claims are unfounded and based on partly incorrect assumptions.

Can Current Experimental Data Exclude Non-Gaussian Genuine Band Shapes in Ultraviolet Photoelectron Spectra of the Hydrated Electron?

“…In ref. [4], we also show that the red spectrum in Fig. 1 is largely identical to a spectrum calculated with the original scattering cross sections [2] and a single Gaussian genuine band shape.…”

“…However, as 3 already pointed out in ref. [4], we cannot completely exclude other potential artefacts. Among them could be unknown biases in the experimental UV spectra used in in ref.…”

“…[2]. Red line: eBE spectrum calculated with cross sections refitted for an escape barrier of V0 = -0.1 eV and a single (1G) Gaussian genuine band shape [4].…”

“…What is important for the current work is that our simulations of the UV spectra of the hydrated electron are largely insensitive to the exact value of V0 as demonstrated in Fig. 1 (see also figure 1 in [4]). Gaussians as derived in ref.…”

“…[1] for a value of the escape barrier around V0 = -0.12eV rather than -1.0eV is actually based on previous sign errors in the derivation, as already pointed out in refs. [4,10,11]. In fact, the cluster data by Coe et al in ref.…”