Studies of Infrared Emission from Shock-Heated Nitric Oxide

Abstract

The infrared emission from nitric oxide mixed with argon was measured. The gas was shock heated to temperatures ranging from 1000° to 2500°K. At the same time the density variations in the heated sample were examined with a Mach—Zehnder interferometer. For varied concentrations of nitric oxide and the range of temperatures covered the observed relative emission intensity at vibration equilibrium is in good agreement with that calculated by using the measured density and the vibrational oscillator strengths derived from the experiments of Penner and Weber. The vibrational relaxation time of nitric oxide is less than 1 μsec, in laboratory time, over the above temperature range, and the corresponding minimum collision transition probability is approximately 10−3.