Temperature Dependence of Optical Absorption Spectra of Solvated Electrons in CD3OD for T .ltoreq. Tc

Abstract

Brodsky and Tsarevsky (J. Phys. Chem. 1984, 88, 3790) developed a theory on solvated electrons (esolv-) which is based on the concept that the excess electron is localized in a medium predominantly by shortrange interactions. Including many-body collective effects of the solvent, they tried also to explain the temperature dependence of the optical absorption spectra of esolv-. To substantiate their point of view, they presented experimental spectra of esolv-in CH30H measured over a wide range of temperatures which were in "satisfactory quantitative agreement" with theory. We have carefully repeated optical absorption measurements on esolv-in CD30D in the temperature range 298 5 T 5 510 K. We report on these experimental results and on the static dipole polarizability (a(0)) of solvated electrons in different media determined by means of optical sum rules. Both results are inconsistent with the above-mentioned theory. The comparison of other ground-state properties of solvated electrons in methanol such as the mean dispersion in position (A$) and the mean quantum mechanical kinetic energy (Q following from the spectra with those obtained by a quantum molecular dynamics simulation shows poor agreement.

Dynamics of fragment recoil in the femtosecond photodissociation of triiodide ions in liquid solution

“…6,9 Diiodide ions in polar liquids also exhibit two broad absorption bands centered near 400 and 740 nm, respectively. 20 The formation of the diatomic product ions upon ultraviolet irradiation of triiodide can thus be monitored through conventional femtosecond transient absorption measurements with resonant probing in the visible spectral region.…”

Time-resolved photoelectron imaging of large anionic methanol clusters: (Methanol)n−(n∼145–535)

“…The solvation of an electron in bulk methanol is similar to that in water, in that the electron resides in a roughly circular cavity of a few angstroms surrounded by approximately six OH groups, 47 while the ground and first excited states are approximated as an "s state" and three "p states," respectively, resulting in a single broad, visible absorption feature. 48 The relaxation dynamics of electrons in methanol have been studied theoretically 49 and in time-resolved transient absorption experiments by several groups. 20,22,[50][51][52][53] The experiments showed substantial variations in the reported time constants, but raised similar issues regarding assignment of the time constants as were found for the hydrated electron.…”

Effect of temperature on the absorption spectra of the solvated electron in 1-propanol and 2-propanol: Pulse radiolysis and laser photolysis studies at temperatures up to supercritical condition

“…In laser photolysis experiments, we used 248 nm laser beam with pulse duration of 20 ns, to produce the solvated electrons by iodine ion (I À ) through so-called resonant photodetachment processes. Then, unlike the pulse radiolysis, we are not able to obtain directly a 'pure' absorption spectrum of the solvated electron in laser photolysis, but a mixed spectrum (recorded at the end of laser pulse) of e À sol and I 2 Àd anion radical, at room temperature, the latter radical has two absorption bands, with l max at 380 and 740 nm, respectively (Dobson and Grossweiner, 1964;Herrmann and Krebs, 1995). Fig.…”

“…For primary alcohols, e.g. methanol, ethanol and 1-propanol, their temperature coefficients are generally 43 Â 10 À3 eV/1C, which higher than that of water of 2.3 Â 10 À3 eV/1C (Wu et al, 2000) indicating that the temperature effect on peak positions of absorption spectra of solvated electrons in (Herrmann and Krebs, 1995), in ethanol: (&) (Jha et al, 1972) and (') , in 1-propanol: (}) (Dixon et al, 1976) and (~) this work, in 1-butanol: (.) unpublished in our work, in 2-propanol: (K) (Arai and Sauer, 1966) and (J) this work, and in water: H 2 O (,), D 2 O (n) Wu et al, 2000).…”

“…For the solvated electrons in alcohols, there have been some reports concerning the studies at different temperatures and pressures by using pulse radiolysis and/ or laser photolysis methods (Jha et al, 1972;Jou and Freeman, 1977;Herrmann and Krebs, 1995;Mostafavi et al, 2004). The results show that absorption spectra of solvated electron are not only dependent on the temperature but also the pressure (Jou and Freeman, 1979;Shiraishi et al, 1988;Christensen and Sehested, 1986;Han et al, 2005).…”