Laser studies of some reactions of ground state oxygen atoms with hydrocarbon molecules

Abstract EN

The dynamics of the hydrogen-abstracting reactions of ground state oxygen atoms, 0(3P), with 3-methylpentane, cyclohexane, and cyclooctane have been studied using a pulse-probe arrangement with 351 nm laser photolysis of N02 producing the oxygen atoms and laser-induced fluorescence being used to determine the vibrational, rotational, and fine structure state distributions of the OH product.

The reactions proceed via a collinear intermediate giving a very low degree of OH rotational excitation.

For the reactions with cyclohexane and cyclooctane the degree of OH vibrational excitation is determined by the exoergicity of the reaction, but steric constraints may explain the reduced vibrational excitation in the case of O with 3-methylpentane.

For 0(3P) + cyclohexane, the results are compared with those obtained in crossed-molecular beam experiments and with the results of a classical trajectory calculation.