The spectra of the trapped electron in 3-methylpentane and 3-methylhexane glasses at 76°K as determined by pulse radiolysis have been found to shift toward the blue on a time scale of mseconds, seconds, and minutes. For 3-methylhexane Xmax is approximately 2000 and 1700 nm at 3 psec and 380 sec, respectively. For 3-methylpentane Xmax is approximately 1900 at 10 psec and shifts to about 1700 nm at 380 sec. The spectra at 380 sec are very similar to those determined by others after 60Co irradiation. Geminate recombination occurs simultaneously with the spectral shifts, but an experiment with added biphenyl indicates that the mechanism involved in the spectral shifts is predominantly molecular reorientation rather than detrapping-retrapping.

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.

. 56, 1889 (1978).The yields and reactions of trapped electrons which absorb in the visible (e,,,-) and infrared (e,,-) have been studied by pulse radiolysis in deuterated aqueous 6-15 M LiCl glasses at low temperatures. At 76 K G(e,,,-) increases and G(ei,-) decreases as the concentration of LiCl is increased, but [G(eVi,-) [LiCI]. At 76 K , where the rates of reaction of ei,-with the scavengers can also be measured, it is found that in each case eVis-and ei,-react more slowly in 12 M LiCl glass than in 6 M LiCI glass, the difference being more marked for SeOj2-. In the absence of scavenger the electron in the smaller yield decays faster. These observations can be rationalized on the basis that electrons can tunnel in either direction between visible and infrared traps before being scavenged, and it seems they cannot be rationalized in terms of direct tunnelling only.G(C12-) is found to be proportional to the electron fraction of CI-.3D20 in the glass and its extrapolated value for pure C1-.3Dz0 is 3.4. It is inferred that C1,-arises mainly from ionization of the D,O bound to C1-. HUGH A. GILLIS, GEORGEG. T E A T H E R~~G E O R G EV . BUXTON. Can. J. Chem. 56,1889Chem. 56, (1978. On a etudie les reactions de ei,-et de eVi,-avec Cu(1l) et Se04'-. A 138 K , la vitesse de la reaction de eVi,-avec SeOa2-augmente lorsque la concentration de [LiCI] diminue alors que sa vitesse de reaction avec Cu(1I) est plus faible et ne depend pas de la concentration de [LiCI]. A 76 K, temperature a laquelle les vitesses de reaction de ei,-avec des piegeurs ont pu aussi Ctre rnesuries, on a trouve que dans chaque cas e,,,,-et ei,-rkagissent plus lenternent dans d e s verres de 12 M LiCl que dans des verres de 6 M LiCI; la difference est la plus marquee avec SeOaZ-. Lorsqu'il n'y a pas de piegeurs, I'electron dans un champ plus faible disparait plus rapidement. On peut rationaliser ces observations en se basant sur I'hypothese que les electrons peuvent reagir par une reaction tunnel dans chaque direction entre les pieges du visible et de I'infrarouge avant d'Ctre piege et il semble quel'on ne peut pas rationaliser les observations en terme uniquement de tunnel direct.On a trouve que G(CIz-) est proportionnel a la fraction electronique de CI-.3D20 dans le verre et sa valeur extrapolee pour C I -. 3 D 2 0 pure est de 3.4. On a deduit que C12-provient principalement de I'ionisation de D Z O lie a CI-.

No abstract

At high solute concentrations (>10"3 M) two types of intermolecular complexes are formed. One of them which absorbs at 500 nm and which is known also from corresponding work in aqueous solutions is characterized by a newly established three-electron bond between two sulfur atoms of two neighboring molecules. The other complex which is formed only in hydrocarbons absorbs at =¿750 nm and results from stabilization of an oxidized sulfur atom in a multicenter interaction complex involving more than two sulfur atoms. The probablity of its formation requires favorable configuration for p-orbital overlap from participating sulfur atoms and is highest for complexes involving sulfur atoms from two separate molecules.