Excitation and relaxation in a high-pressure CO laser

Strong laser emission is reported from a transverse discharge at relatively high pressure in both pure CO and CO-He at room temperature. Calculations of excited population distributions produced by electron CO collisions show an initial distribution that is approximately Boltzmann at a vibrational temperature
T_{\upsilon}\simeq 6700
K. The laser emission spectra exhibit complete inversion. Time delay measurements are in good agreement with known V-V relaxation times in CO, and the
p\tau
product shows the constancy expected of vibrational relaxation. The evolution of inversion from a near Boltzmann distribution can only be explained by anharmonic oscillator relaxation effects.