ROVIBRATIONAL-STATE-DEPENDENT COLLISIONS OF C2H4-KR AT LOW-TEMPERATURES

Light-induced drift experiments at temperatures between 130 and 300 K have been performed on C2H4 with Kr as a collision partner. The experi mental results for various rovibrational transitions in the nu7 fundam ental vibrational band are expressed in terms of the relative change i n collision rate upon excitation, DELTAnu/nu, as a function of the mea n relative speed g(rms) between the collision partners. For low g(rms) , the collision rate nu is found to depend strongly on the rotational states involved. For high g(rms), the rotational dependence is relativ ely weak, and the values of DELTAnu/nu converge to what is interpreted as the pure vibrational contribution.