A kinetic study of the interaction between atomic oxygen and aerosols

Abstract

This study was concerned with the effects of aerosols on the kinetics of disappearance of atomic oxygen. Atomic oxygen was generated by a 2450 MHz microwave discharge, and the kinetics of disappearance measured in a fast flow system using N0₂ titration.

The recombination coefficient, for heterogeneous wall recombination was determined for clean Pyrex, H₂SO₄ coated wall, and (NH₄)₂SO₄ coated wall. The values of γ were 4.97 x 10^-5, 2.05 x 10^-5, and 1.90 x 10^-5 respectively.

A rapid exothermic chemical reaction was found to occur between atomic oxygen and NH₄C1; the products, as determined by mass spectrometry, were NH₃, NO, H₂O, HC1.

An NH₄Cl aerosol was generated by gas phase reaction of NH₃(g) with HCl(g), The aerosol particles were approximately spherical and nearly monodisperse with a mean diameter of 1.6 ± .2 μm.

The rate constant {k_AERO) for the disappearance of atomic oxygen in the presence of an NH₄Cl aerosol was measured. For an aerosol concentration of 4.75 x 10³ µg/m³. a value of k_AERO = 2.75 ± .5 sec^-1 was found,