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

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 k_1,∞ = (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, k_1,∞ decreases. These results serve as a reference for statistical adiabatic channel model calculations of the recombination rate.