Rotational relaxation rates for the J = 0–1 transition of N₂O by self-collisions and foreign gas collisions

Abstract

Time domain techniques using pulse methods in microwave spectroscopy have been employed to determine the population and coherence decay rates, 1/T ₁ and 1/T ₂, for the J = 0–1 rotational transition of ¹⁵N₂O. The pressure dependence of both relaxation rates has been investigated for the pure gas. Pressure broadening of the line (∼ 1/T ₂) has also been studied for mixtures with O₂, N₂, air and the rare gases He, Ne, Ar, Kr and Xe. The observed transient emission signals were analysed by the standard model of constant coherence decay rates and also assuming dependence of the rates on the speed of the absorber molecules. The experimental results are compared with predictions from theoretical treatments of the binary collisions.