Dissociation Rate Constants of Alkylbenzenes from Hot Molecules Formed by 158-nm (F2 Laser) Irradiation

Article abstract of DOI:10.1021/j100194a037

Toluene, p-xylene, deuterated p-xylene, and mesitylene under low-pressure conditions as well as p-xylene under high-pressure conditions were studied with a 158-nm laser.Rise curves of the photoproducts were observed by the method of nanosecond laser photolysis.The ground-state alkylbenzenes with an internal energy of 8 eV are formed by internal conversion following the laser excitation.The alkylbenzenes dissociate to the corresponding benzyl-type and phenyl-type radicals via the hot molecule state.The dissociaton rate constants were 9.3 (+/- 0.7) x 10⁷ s^-1, 1.5 (+/- 0.3) x 10⁷ s^-1, 4.6 (+/- 0.4) x 10⁶ s^-1, and 3.0 (+/- 0.9) x 10⁶ s^-1, respectively.Dissociation rate constants of the C-H bond in the methyl group of the alkylbenzenes were estimated from these results and compared with previous predictions.