Photodissociation dynamics of the 2-propyl radical, C3H 7

Abstract

The photodissociation of 2-propyl leading to propene+H was investigated with nanosecond time resolution. A supersonic beam of isolated 2-propyl radicals was produced by pyrolysis of 2-bromopopane. The kinetic energy release of the H-atom photofragment was monitored as a function of excitation wavelength by photofragment Doppler spectroscopy via the Lyman-α transition. The loss of hydrogen atoms after excitation proceeds in α position to the radical center with a rate constant of 5.8 × 107 s-1 at 254 nm. Approximately 20% of the excess energy is deposited as translation in the H-atom photofragment. In contrast 1-propyl does not lose H atoms to a significant extent. The experimental results are compared to simple Rice-Ramsperger-Kassel-Marcus calculations. The possible reaction pathways are examined in hybrid density functional theory calculations. © 2007 American Institute of Physics.