HIGH-PRESSURE RANGE OF THE ADDITION OF HO TO HO, NO, NO2, AND CO .1. SATURATED LASER-INDUCED FLUORESCENCE MEASUREMENTS AT 298 K

Saturated laser induced fluorescence is used for the sensitive detection of radicals in high pressure gases. The method and its application to a series of addition reactions of HO radicals in the high pressure regime are described. Experiments between 1 and 150 bar of the bath gas He allow for falloff extrapolations to the high pressure limit of the recombination reactions. Limiting rate constants (in cm(3) molecule(-1)s(-1)) of 2.2X10(-11) for HO+HO-->H2O2, of 3.3x10(-11) for HO+NO-->HONO, of 7.5X10(-11) for HO+N0(2)-->HON0(2), and of 9.7X10(-13) for HO+CO-HOCO (and H+CO2) are derived at 298 K. (C) 1995 American Institute of Physics.