Pulse radiolysis studies of time dependent spectral shifts of the solvated electron in ethanol and deuterated ethanol glasses at 76 K

Abstract

The initial (?200 nsec) spectra of the trapped electron are similar in C2H5OH, C2H5OD, C2D5OH, and C2D5OD glasses at 76 K with λmax ∼1300 nm. The kinetics of the spectral shifts to the stable values of λmax near 540 nm are similar for C2H5OH and C2H5OD and resemble the kinetics of a series of first order processes or of tunneling reactions. Structure seems to be present in the partially relaxed spectra and may result from specific geoemetrical orientations of first solvation shell molecules.

Evidence for a second kind of trapped electron in some deuterated aqueous glasses at low temperatures. A pulse radiolysis study

“…Similar changes have been seen in hydrocarbon (21) and alcohol glasses (8,22). Dipole relaxation was invoked to explain these changes in hydrocarbon glasses (21).…”

“…Dipole relaxation was invoked to explain these changes in hydrocarbon glasses (21). For the alcohol glasses the changes were again attributed to reorientation of dipoles about the trapped electron (8,22) electron tunnelling from shallow to deep traps (8). In the EG/D20 glass there is growth at short wavelengths which we believe is due to retrapping of electrons from the infrared band (see below).…”

Chapter 3. Dispersive kinetics in condensed phases

“…Assuming that for the conversion of 'infrared' electrons into 'visible' electrons the deep trap simulates the role of scavenger, the spectral relaxation kinetics should also follow equation (1 1). It was shown4 to be the case for the results obtained by Miller et aL4' for several undoped alcohols at 77 K in the range 10-'-102s after pulsed irradiation, by Klassen et al 42 on spectral shifts in ethanol at 76K, by Ogasawara and K e ~a n ~~ for solvation of electron produced by ruby laser photoionization of 5 x M #?-naphtholate in ethanol containing 0.1 M NaOH at 83 to 123 K, and by Baxendale and Sharpe4 on electron transfer in propan-1-01 at 108K. Thus there is no doubt that both spectral relaxation and electron scavenging in a wide range of systems follow equation (11).…”

Electron solvation in methanol revisited

“…Many pulse radiolysis studies were made in alcohols cooled close to freezing point to suciently slow down the solvation process. Most of the suggested mechanistic ideas originate from studies done in the seventies Wardman, 1971, 1973;Baxendale and Sharpe, 1976;Chase and Hunt, 1975;Klassen et al, 1975;Gilles et al, 1977;Okazaki and Freeman, 1978). A simple two-state stepwise mechanism interpreted the results in terms of two absorbing localized species: à`p resolvated'' and an``equilibrated'' one.…”

“…A simple two-state stepwise mechanism interpreted the results in terms of two absorbing localized species: à`p resolvated'' and an``equilibrated'' one. The blueshifting model contained one single localized species to absorb, whose spectrum temporarily shifted towards the blue wavelengths (Klassen et al, 1975;Gilles et al, 1977;Okazaki and Freeman, 1978). The combination of the two models was also proposed (Ogasawara et al, 1981).…”