Vibrational energy transfer processes in gaseous systems at high temperatures

A study has been made of the rate of vibrational excitation in shock heated CO for the temperature range l300K - 2500K, by observation of the infrared emission behind the incident shock wave. Care was taken to eliminate'impurity effects and the non uniformity of the flow was accounted for in the prescribed manner. The first measurements were made on the fundamental and overtone of CO in the pure gas and CO/Ne mixtures. The experimental data was reduced using kinetically derived equations, which incorporated the Landau-Teller ratios between the rate constants. For TCO-CO the Landau-Teller constants were found to be A = -22.2; B = 160.2 and for TCO-Ne A = -21.66; B = 148.9. The separate observations of the levels indicated that the population of the v = 2 level was by successive single quantum transitions. It was concluded that the Landau-Teller ratio of the rate constants k21 : k10 = 2 : 1, was incorrect, in the case of the anharmonic oscillator. The coefficient was thought to lie between 2.2 and 2.4. It was demonstrated by computer calculations, using selected models, that the equations used in the reduction of experimental data were inadequate for real systems. Thus studies using the equations were thought to be subject to a small systematic error