ROTATIONAL AND SPIN-ORBIT EFFECTS IN THE DYNAMICS OF O(P-3(J))+HYDROCARBON REACTIONS .1. EXPERIMENTAL RESULTS

Laser photolysis of NO2 has been combined with laser-induced fluoresce nce detection of the nascent OH product to investigate the dynamics of the reactions of O(P-3) with a series of saturated hydrocarbons. We c onfirm previous observations of very low fractions of OH rotational en ergy release for the higher homologues such as isobutane and cyclohexa ne. By photolysing NO2 at shorter wavelengths to produce translational ly hotter O(P-3) atoms, we have been able to extend the measurements t o the previously unstudied parent members of the series, methane and e thane. Similar low levels of rotational energy release were found, sug gesting that the previously proposed strong collinear constraint also applies to CH4 and C2H6. No preference for either OH Lambda-doublet co mponent was observed, also consistent with a collinearly constrained r eaction. The OH spin-orbit states were found to be nonstatistically po pulated. In part II we present a detailed discussion of the potential source of the spin-orbit propensities. (C) 1997 American Institute of Physics.