Oscillation, Rotation, and Spin Relaxation in NO

Abstract

The sound absorption and velocity of NO gas at 293°K was measured from f/p=5×10⁴ to 10⁷ cps/atmos using an ultrasonic pulse method. A maximum of the absorption at 4×10⁵ cps/atmos is ascribed to the relaxation of the oscillational degree of freedom. (τ_osc=4×10^—7 sec at 1 atmos.) According to the absorption at high f/p values, τ_spin≈4τ_rot (=2.5·10^—9 sec at 1 atmos) seems probable. The result is compared to the corresponding data of O₂ and N₂.