H + H 2O→OH + H 2: absolute reaction cross sections and OH state distributions

Abstract

The nascent state distributions of OH produced in the reaction H + H 2O→OH + H 2 were probed by fast atom-laser-induced fluorescence experiments. Translationally hot H atoms were formed by photolysis of HI at 250 and 270 nm leading to H + H 2O c.m. collision energies E of 176 and 143 kJ/mol. With a calibration method using HNO 3 photolysis as OH-precursor absolute reaction cross sections of 0.27 ± 0.12 Å 2 ( E = 176 kJ/mol) and 0.17 ± 0.07 Å 2 ( E = 143 kJ/mol) were measured. The OH rotational and vibrational state distributions as well as reaction cross sections are compared with previous theoretical results based on quasiclassical trajectory calculations on an ab initio potential energy surface.