Gamma radiolysis of 3-methylpentane and ethanol glasses containing triphenylamine

Abstract

Gamma irradiation of a 3-methylpentane (3MP) glass containing triphenylamine (TPA) at 72–74K produces the trapped electron (e 3MP −) and another negative species (e TPA −). Like e TPA − absorbs in the I.R. with a peak at 1.6 μm. In contrast with e 3MP −, e TPA − is not bleached by 1.9 μm light, has a narrower absorption band, and exhibits a broader E.S.R. singlet with ΔH ms = 6.6 G . At 72K, the 100 eV yield, G(e TPA −), increases with increase in TPA concentration and has the value 1.3 at 10 −2 mol dm −3 TPA while G(e 3MP − decreases from 0.4 in neat 3MP to 0.1 at 10 −2 mol dm −3 TPA. Gamma irradiation of an ethanol glass containing TPA at 77K does not produce an infrared absorption but produces peaks at 440 and 410nm in addition to the trapped-electron peak at 540nm. The peaks at 440 and 410nm are attributed to TPA − because absorbance at these peaks increases with increase in TPA concentration and that at 540nm decreases. The totality of the results for alcohol and 3-MP glasses suggests that e TPA − is an electron in a trap similar to that of e 3MP − but modified by the presence of a TPA molecule whose positive nitrogen end is oriented toward the electron.