Electronic absorption spectra of cation-radicals of alkanes and CCl4 by a combined optical and ESR studies for γ-irradiated rigid solutions

The optical absorption spectra of the cation-radicals of various normal and cycloalkanes are confirmed by a parallel ESR and optical measurement. The absorption maxima of the normal alkane cation converge to about 1.2.μ and the absorption thresholds lie in the near IR region, contrary to the expectation from molecular orbital analyses. The optical absorption spectra of the cations are in consistence with the photoelectron and photodecomposition spectra. The apparent difference in the behavior of the alkane cations in the CCl3F and the CCl4 matrices under photo and thermal excitation is consistently accounted for. The cation-radical of CCl4 in both CCl4 and CCl3F matrices is characterized by its optical and ESR spectra.