Energy-transfer dynamics of high-pressure rovibrationally excited molecular H2

Abstract

The energy-transfer dynamics of high-pressure molecular H(2) gas initially prepared in the |X (1)Sigma(g) (+),v = 1,J = 1 state using stimulated Raman pumping are probed with rotational Raman scattering. A computer simulation that incorporates the effects of collision-induced vibrational energy transfer is described and used to fit the experimental Raman scattering results obtained as a function of the pump/probe delay time. The 4.78 x 10(-14) +/- 3.85 x 10(-16) cm(3) s(-1) molecule(-1) vibrational energy-transfer rate for decay from the |X (1)Sigma(g) (+),v = 1,J = 1 >state compares well with other lower-pressure studies.

Calculations of V−V Transfer Rates in H2 and Comparison with Experiment

“…is consistent with the previously reported experimental values of Kreutz et al 2 (K) and Saiki et al 3 (S). However, for nonresonant processes, comparison of the experimental rates with the results of previous semiclassical calculations 4 showed the theoretical rate constants to be too slow, by a factor of approximately 3.…”

“…Recent results from Ahn, Adamovich and Lempert (AAL) on vibration-to-vibration (VV) transfer in H 2 have shown interesting behavior. The measured rate constant for the nonresonant process, is consistent with the previously reported experimental values of Kreutz et al (K) and Saiki et al (S). However, for nonresonant processes, comparison of the experimental rates with the results of previous semiclassical calculations showed the theoretical rate constants to be too slow, by a factor of approximately 3.…”

“…Comparison of experimental VV rate constant values reported in AAL ● (ref ), FC ◼ (ref ), K ▲ (ref ), and S ◆ (ref ). The values are rotation-averaged and represent v 1 = 1, v 2 = v − 1 → v 1 = 0, v 2 = v .…”