Electron spin resonance studies on trapped electrons and free radicals in .gamma.-irradiated isobutyl vinyl ether glasses

1969 ◽  
Vol 73 (11) ◽  
pp. 4017-4020 ◽  
Author(s):  
Kozo Tsuji ◽  
Ffrancon Williams
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Vinyl Ether ◽  
Electron Spin ◽  
Trapped Electrons ◽  
Spin Resonance ◽  
Gamma Irradiated

Detection of trapped electrons in organic glasses after gamma irradiation at 4.2 °K by electron spin resonance spectroscopy

1967 ◽  
Vol 45 (22) ◽  
pp. 2723-2727 ◽  
Author(s):  
D. R. Smith ◽  
J. J. Pieroni
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Dipole Interaction ◽  
Necessary Condition ◽  
Resonance Spectroscopy ◽  
Hydrogen Atoms ◽  
Trapped Electrons ◽  
Organic Glasses ◽  
Spin Resonance ◽  
Gamma Irradiated

Several organic glasses which are known to form trapped electrons when gamma irradiated at 77 °K have been irradiated at 4.2 °K and examined by electron spin resonance (e.s.r.) at the same temperature. In each case an absorption is observed which is probably due to trapped electrons. In three cases, the yield of trapped electrons at 4.2 °K seems to be as great as at 77 °K. In one case, a glassy alkane, the yield is enhanced at 4.2 °K. Trapped electrons in ethanol give a narrower e.s.r. line at 4.2 °K than at 77 °K, suggesting less orientation in the solvent cage.Trapped hydrogen atoms are not detected after irradiation at 4.2 °K. Contrary to prediction, hydrogen atoms are also not detected after post-irradiation photolysis of the trapped electrons.The results suggest that electron traps exist prior to irradiation and that molecular orientation via electronic dipole interaction is not a necessary condition for electron trapping. The results do not distinguish between trapping in solvent defects or trapping via electron-induced polarization of molecular orbitals.

Electron spin resonance observations on trapped electrons and free radicals formed in olefins at 77 °K by γ-irradiation

1967 ◽  
Vol 45 (8) ◽  
pp. 833-837 ◽  
Author(s):  
D. R. Smith ◽  
F. Okenka ◽  
J. J. Pieroni
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Hydrogen Abstraction ◽  
Γ Irradiation ◽  
Trapped Electrons ◽  
Spin Resonance ◽  
The Matrix ◽  
Subsequent Exposure ◽  
Branched Chain

Electron spin resonance (e.s.r.) methods have been used to search for the γ-ray-induced formation of trapped electrons and free radicals in 13 straight-chain and branched-chain terminal olefins at 77 °K. When e.s.r. spectra were observed they were used to identify the species present. Changes induced by subsequent exposure to visible and ultraviolet (u.v.) light were investigated. Trapped electrons were observed in three olefins that exist as glasses at 77 °K, hexene-1, hexene-2, and 2-methylbutene-1, but were not detected in two other glassy olefins, possibly because of rapid annealing. No trapped electrons were found in polycrystalline olefins at 77 °K. The possibility that CO2− ions have been misinterpreted as trapped electrons in these and other systems is discussed and eliminated. The formation and behavior of free radicals and trapped electrons in irradiated 2-methylbutene-1 are analogous to those previously reported for 2-methylpentene-1 under similar conditions. These observations support the hypothesis that in these two systems ions produced initially isomerize rapidly, leading to the formation of the free radicals detected by e.s.r. The results of a subsidiary experiment suggest that hydrogen abstraction from the matrix is induced by u.v. photolysis of the radicals present in 2-methylpentene-1.

Electron spin resonance studies of radiation damage. Part IV. The effect of photobleaching on the trapped radicals in gamma irradiated 2-methyltetrahydrofuran glasses at 77 °K

1970 ◽  
Vol 48 (21) ◽  
pp. 3453-3455 ◽  
Author(s):  
F. P. Sargent
Keyword(s):  
Electron Spin Resonance ◽  
Radiation Damage ◽  
Electron Spin ◽  
Trapped Electrons ◽  
Spin Resonance ◽  
Gamma Irradiated

The concentration of trapped radicals was found to decrease during the course of photobleaching trapped electrons in gamma irradiated 2-methyltetrahydrofuran glasses at 77 °K.

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