Charge Transfer from the Carbon Tetrachloride Radical Cation to Alkyl Chlorides, Alkanes, Alkenes and Aromatics

Abstract

Abstract Charge transfer from carbon tetrachloride radical cations to 17 solutes (alkyl chlorides, n‐ and c‐alkanes, alkenes and aromatics) was studied by pulse radiolysis. ‐ At gas‐phase ionization potential differences Δ I = ( I CCl4 ‐ I s ) smaller than 0.8 eV rate constants of the reaction magnified image up to two orders of magnitude lower than expected for a diffusion controlled reaction have been determined. The dependence of the rate constants on the ionization potential differences k vs. Δ I is explained in terms of a two‐step process consisting of migration of solvent cations and electron transfer from the scavenger molecule to the solvent cation. The probability of the last step was calculated using the Franck‐Condon principle. In the framework of a simplified model taking into account vibrational stretching and deformation modes reasonable fits of the k vs. Δ I behaviour were obtained.