Iodine atom loss kinetics in internal energy selected 1-iodoalkane cations by imaging photoelectron photoion coincidence spectroscopy

摘要: Abstract Imaging photoelectron photoion coincidence (iPEPICO) spectroscopy has been used to determine 0 K appearance energies for the unimolecular dissociation reactions of several energy selected straight chain alkyl iodide cations 1-CnH2n+1I+ → CnH2n+1+ + I , (n = 3–7). The iodine atom loss, yielding in fact 2-alkyl radical cation up n = 6, was determined be 9.836 ± 0.010, 9.752 ± 0.010, 9.721 ± 0.010, 9.684 ± 0.010 and 9.688 ± 0.015 eV 1-C3H7I, 1-C4H9I, 1-C5H11I, 1-C6H13I, 1-C7H15I, respectively. In 1-iodohexane smaller molecules, these correspond transition state along 1-iodoalkane cation → 2-iodoalkane reaction path, can conjunction with isodesmic reverse barriers dissociative photoionization. small kinetic shift is indicative little H tunneling during isomerization. Directly computed show that run-of-the-mill computational approaches are limited use when applied open shell systems containing period 5 elements. Hindered rotors were found play a minor role internal distribution rate constants.