Photodetachment Spectra of Trapped Electrons in Spherical Potentials

Abstract

The line shapes of absorption spectra of trapped electrons in metal-ammonia solutions, water, and alcohols are compared in detail with photodetachment spectra of spherical potentials, which have been applied extensively in liquid helium. A qualitative discussion is presented to point out some uncertainty in the role of the bound-bound transition ls -2p, which is predominant in the dielectric continuum model. Apart from the uncertainty related to the effective mass of the polaron, the coherence of the 2P state in the more realistic fluctuation potential is likely to be small. A molecular model for the trapped electrons is briefly described.

Photostimulated electron detrapping and the two-state model for electron transport in nonpolar liquids

“…trend (concurrent with the blue shift of the absorption spectrum) 42 agrees well with the theoretical analyses in the "bubble model" 9,16,[43][44][45][46][47] of solvated electron discussed in Sec.…”

“…, . This model, also known as the Wigner-Seitz model, 9,43,44,60 or the electron bubble model, 16,[45][46][47] was originally suggested for electrons in liquid 4 He. Since for this liquid V 0 ≈1 eV (due to the negligible polarizability of He atoms) and a ≈ 17-20 Å (due to the low surface tension), 16,47 the well is deep, supporting several bound-tobound (bb) transitions (1s-1p 61,62 and 1s-2p) 45,61 in addition to bound-to-continuum (bc)…”

“…The simplest of such models is that of an electron trapped in a rectangular spherical potential well of depth U and a hard core radius a. This remarkable success prompted several workers 9,43,44,71 to use the bubble model for electrons in low-temperature, vitreous hydrocarbons which, like liquid 4 He, also exhibit large positive V 0 . According to these models, the entire absorption spectrum for such electrons originates through a bc transition from the ground 1s state.…”

Electron Mobilities and Ranges in Liquid Ethers: Ion-like and Conduction Band Mobilities

“…It is not clear which, if any, of the specific mechanisms might apply to electrons in ethers, but it is tempting to speculate that the great breadth of the optical absorption spectra of solvated electrons is due to a large variation in trap depths, and that most of the observed spectrum in an ether is due to bound-continuum transitions. The possible subdivision of the optical spectra of solvated electrons into bound-bound and boundcontinuum transitions has received attention recently (29)(30)(31)(32).…”

The Solvated Electron in Polar Organic Liquids

“…The experimental data obtained in recent years leads to the conclusion 26 » 27 that optical absorption is determined mainly by the transition to a continuous spectrum. On the basis of this assumption, it can be shown 28 that, by specifying the simplest form of the potential curve, namely a rectangular well, it is possible to achieve a satisfactory agreement between the theoretical and experimental absorption curves when certain parameters are chosen. Certain important characteristics of solvated electrons have been calculated 29 from the shape of their absorption line using threshold formulae and it was concluded that the lower energy side of the absorption band corresponds to photoionisation, the effective interaction in the final state being short-lived.…”