Atomic-Nitrogen Recombination

Abstract

Three-body and wall recombination coefficients of atomic nitrogen were measured using an electron spin resonance spectrometer to determine the atomic nitrogen concentrations. Studies were made of nitrogen gas at pressures from 3 to 35 torr flowing in a cylindrical tube and nonflowing nitrogen gas at pressures from 0.3 to 7 torr. The three-body recombination coefficient k1 with molecular nitrogen as the third body was found to be (2.25±0.2)×10−32 cm6 sec−1. The wall recombination probability, λ, of quartz was found to range from 7×10−6 to 5×10−4, decreasing with increasing oxygen impurity; the variation for Teflon was measured to be from 2×10−7 to 2.5×10−5, increasing with increasing oxygen content. The sum of the two-body radiative recombination and two-body wall recombination was a significant part of the total atom recombination; the sum of these coefficients ranged from 0.35×10−15 cm3 sec−1 to 2.8×10−15 cm3 sec−1. For intervals up to 2 sec following atomic-nitrogen formation, the data indicate a slower decrease of atom concentration than can be accounted for by the measured mechanisms of recombination. The possible existence of an atom-forming mechanism in the afterglow is discussed.