Vibrationally excited hydroxyl in the products of the atomic hydrogen + nitrogen dioxide reaction

Abstract

The presence of vibrationally excited OH in the products of the H + N02 reaction has been confirmed by detailed spectroscopic analysis of the IR emission. The observations were carried out in a fast flow discharge reactor at room temperature and at total pressures near 1 Torr. Although diffusion limited mixing was evident in our system, the presence of vibrationally excited OH restricts the range over which the H + N02 reaction can be used as a source of ground state OH for subsequent reaction studies.

Rate constant for the reaction atomic hydrogen + nitrogen dioxide from 195 to 400 K with FP-RF and DF-RF techniques

“…The reaction between hydrogen atoms and nitrogen dioxide + N02 -* OH + NO (1) with = -29 kcal/mol has drawn increased attention for several important reasons. Studies of the absolute reaction rate constant1-6 and the energy states of the products of the reaction7-12 are of particular interest since it is now known that vibrationally excited OH is produced in reaction l. [7][8][9][10] In addition to this fundamental interest, reaction 1 has been used as a source for vibrationally excited OH for chemical kinetic studies of that species itself.10 Reaction 1 has also been used in discharge flow studies to prepare ground-state OH,13 and many of the currently accepted rate constants of OH with molecules and radicals come from this type of study.14 Lastly, reaction 1 has served as the major calibration reaction for H atoms in discharge flow experiments. Secondary processes become important if the titration is carried out at relatively high [H]0, and then the overall stoichiometry changes from 1:1 to 1:1.5 H atoms to N02 molecules.…”