High-pressure range of the addition of HO to HO. III. Saturated laser-induced fluorescence measurements between 200 and 700 K

Abstract

The addition of HO to HO was studied by saturated laser induced fluorescence at temperatures between 200 and 700 K and at pressures of the bath gas helium up to 100 bar. In combination with earlier measurements at 298 K, a set of falloff curves is constructed for the given temperature range. The limiting high-pressure rate constant for the reaction HO+HO(+He)→H2O2(+He) follows as k1,∞=(2.6±0.8)×10−11 (T/300 K)0±0.5 cm3 molecule−1 s−1, practically independent of the temperature between 200 and 400 K. At higher temperatures, k1,∞ decreases. These results serve as a reference for statistical adiabatic channel model calculations of the recombination rate.