Electronic spectra and related ionic effects in gamma-irradiated organic glassy solids

Abstract

Garmna irradiation at 77°K of organic glassy solids which contain solutes RX or M provide evidence for the formation of R and X-by dissociative electron attachment, M-by simple electron attachment and M+ by charge exchange with appropriate components of the matrix. Benzyl chloride and naphthalene illustrate the two types of solute. Detection in all cases was based upon electronic absorption spectra. Failure to observe M+ in ethanol and other polar media indicates efficient formation of such protonated species as RQHZ. Benzyl radicals were observed in glassed ethanol containing benzyl acetate following gamma irradiation and equivalent yields of acetic acid were found in the subsequently thawed samples. It appears that ionic processes may play a major role in radiation chemistry.

Photomodulated voltammetry investigations on the benzyl radical

“…The benzyl radicals were generated by the direct photolysis of diphenylacetone (1) in MeCN, PC, DMF and DMSO. Solutions of 3 × 10 −3 , 6 × 10 −3 or 9 × 10 −3 M were slowly flowed (1-2 ml/min) through the cell, after carefully degassing the solution with argon.…”

“…The generation of benzyl radical and substituted benzyl radicals can be performed by a large variety of methods like γ-radiolysis [1], pulse radiolysis [2], electrolysis [3], hydrogen abstraction [4][5][6] but the most popular method remains photolysis.…”

Radiation Chemistry

“…Hamill et al (97), continuing earlier post-irradiation spectroscopic studies of ions in glasses, have observed both dissociative electron attach ment and electron capture by solutes. Triphenylmethyl chloride and benzyl chloride in tetrahydrofuran glasses exhibit the former, while napthalene and biphenyl in 3 methyl pentane, 2 methylpentene-1 glasses exhibit the latter.…”

“…Hamill et a1. (97) have observed several absorption spectra in hydrocarbon glasses containing aromatic hydro carbon solutes. The difference in absorption spectra between 3-methylpentane glasses with and without 25 per cent 2-methylpentene-l added are attributed to hydrogen atom adducts with the aromatic hydrocarbons.…”

Reactivity of Organic Halides toward the Mobile Electron in Methyltetrahydrofuran Glass

“…absorption of trapped electrons in polar glasses, such as alkaline ice (1 -3), alcohols (4)(5)(6)(7)(8)(9)(10)(11)(12), water-alcohol mixtures (13)(14)(15), and methyltetrahydrofuran (16)(17)(18)(19)(20)(21)(22)(23)(24)(25). One objective of scavenger studies has been to produce new anions from the reaction of the mobile electron with the scavenger molecule.…”