The spectra and the relative yield of solvated electrons produced by resonant photodetachment of iodide anion in ethylene glycol in the temperature range 296≤T≤453 K

We have produced solvated electrons (e(solv)(-)) in ethylene glycol (EG) by irradiation of a 248 nm laser pulse in the charge-transfer-to-solvent (CTTS) band of I- (resonant photodetachment). We report on the optical absorption spectra of e(solv)(-) as a function of temperature. A red-shift of the position of the absorption maximum, Delta h omega(max) approximate to -0.4 eV, corresponding to d((h) over bar omega(max))/dT=-(2.49 +/- 0.07) x 10(-3) eV K-1 in the temperature range 296 less than or equal to T less than or equal to 453 K is reported. The observed absorbance of e(solv)(-) at (h) over bar omega(max) increases by a factor of about 60 when the temperature is increased from 296 to 453 K. This effect can be explained only partially by the favorable red-shift of the CTTS spectrum of I- with respect to the laser wavelength by increasing the temperature. The self diffusion coefficient in EG is by a factor of 25 lower than in water at 298 K and increases strongly with temperature. It is concluded that a reaction step with a diffusion controlled escape probability for the electron determines the yield of e(solv)(-). The results are, therefore, analyzed according to a simple kinetic model proposed by Staib and Borgis [J. Chem. Phys. 104, 9027 (1996)]. (C) 2000 American Institute of Physics. [S0021-9606(00)01613-5].