Influence of the radical group upon total reaction cross-section molecular beam study of the K + RI → KI + R (R = CH₃, C₂H₅, C₃H₇) reactions

Abstract

Relative values of the total reaction cross-section for the crossed molecular beam K + RI → KI + R (R = CH₃, C₂H₅, C₃H₇) reactions have been measured at low collision energies. An estimation of the influence of the radical group upon the reaction cross-section was made. At E_T = 0·18 eV of collision energy we found 20A², 30A² and 39A² for the propyl, ethyl and methyl reactions, respectively. These results reveal a larger steric factor with the size of the alkyl group. This is consistent with the (observed) increase in the backward character of the product (KI) centre of mass angular distributions as the reagents' alkyl group size increases.