We report the first direct measurement of the vibration-to-vibration (V-V) and vibration-to-translation (V-T) rates for vibrational relaxation out of the ν=2 vibrational level in hydrogen gas. Time domain photoacoustic spectroscopy was used to monitor the collision dynamics after excitation into ν=2 through overtone stimulated Raman pumping. The V-V relaxation rate is found to be (1-4) × 10-14 cm3 s-1 molecule-1 and the V-T rate constant is (0.6-2) × 10-15 cm3 s-1 molecule-1 for normal hydrogen at 298 K.
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy
- Physical and Theoretical Chemistry