Vibrational Relaxation Rates And Pathways In Highly Excited Molecules

The techniques of laser double resonance or near-infrared fluorescence detection in combination with direct excitation of overtone vibrations provide detailed data on the rates and pathways of collisional energy transfer in hydrogen fluoride and deuterium fluoride. These measurements yield the self-relaxation rate constants for HF(v=1,2,3,4,5) and DF(v=1,2). In addition, they determine the relative importance of the vibration-vibration and vibration-translation, rotation energy transfer pathways for v> or = 2 in both molecules. Applying these techniques at higher temperatures gives the self-relaxation rate constants between 300 and 700 K for HF(v=1-5). Using different partners permits the determination of the rate constants for collisional relaxation of HF(v=3,4,5) by H2, D2, CH4, CD4, and C02.