NO line parameters measured by CO laser transmittance

Spectral coincidences between the fixed-frequency CO laser line and the NO fundamental absorption band are utilized in order to obtain line shape parameters (strengths, pressure broadening coefficients, linewidths) by taking transmittance as a function of pressure. The frequency offset between the laser line and the center of the absorbing line is determined accurately via heterodyne measurements of the CO laser frequencies and NO absorption frequencies. The liquid-nitrogen-cooled laser and associated optics, data reduction techniques, and molecular spectroscopic states used are indicated. The line shape parameters are useful in remote sensing of atmospheric pollutants and measurements of the concentration of a single species in a reacting system to determine chemical reaction rates.