Nonequilibrium vibrational kinetics of carbon monoxide at high translational mode temperatures

Abstract

Recent experiments and analyses involving vibration-to-vibration (VV) pumped carbon monoxide are presented. Pure CO, and COAr mixtures, in a flowing-gas cell, are vibrationally excited by absorption of CO laser radiation. The pump laser is a slow-flow liquid-nitrogen wall-cooled device, which can be operated in either Q-switched or cw mode for these experiments. There is output down to the v=1−0 vibrational transition ( Q-switched) or v=2−1 (cw). CO has been VV pumped in these experiments to very high vibrational quantum levels, at partial pressures up to 65 Torr. The rotational/translational mode temperature has been measured by emission spectroscopy of rotationally resolved Swan bands of C 2 formed from reaction of the VV pumped CO. Measured rotational mode temperatures up to 1500 K have been achieved with strong VV pumping. Low levels of ionization have been observed under these extreme pumping conditions. Results of time-resolved experiments exploring the kinetics are presented. These results are analyzed using a time-dependent kinetic master equation modeling code for the vibrational state kinetics.