Collisional energy transfer of vibrationally highly excited CS2. II. Temperature dependence of 〈Δ<i>E</i>〉 from experiments in shock waves and laser-heated reactors

Abstract

Collisional energy transfer between vibrationally highly excited CS2 molecules and 22 different collision partners has been measured directly by time resolved UV absorption spectroscopy after laser excitation. Experiments at temperatures up to 1200 K were performed in a reactor heated by cw CO2 laser radiation. Experiments at higher temperatures (up to 2400 K) with the collision partner Ar were done with pulsed laser excitation behind reflected shock waves. At all temperatures a marked dependence of the average energy 〈ΔE〉 transferred per collision on the excitation energy is noted. Also the molecular size of the deactivating molecule has a large influence on 〈ΔE〉. The temperature coefficients of 〈ΔE〉∝Tn are small in all cases. They vary between n=−0.6 for n-heptane and n=+1.0 for Ne.