A time-resolved study of rotational energy transfer into A and E symmetry species of 13
Rotational energy transfer processes into the A and E symmetry species of the symmetric top molecule 13CH3F have been studied. In this time-resolved double resonance experiment a tunable millimeter/ submillimeter wave spectrometer was used to monitor the change in strength of rotational transitions in the v3 vibrational state after a Q-switched CO2 laser pumped the K = 3, J = 5 level in v3. A simple numerical simulation of rotational energy transfer allowed the 13CH3F system to be modeled and collisional energy transfer rates to be obtained from the data. Two important processes were studied. The first, a process that obeys the spin statistic selection rule ΔK = 3n has a rate of 29 ±6 ms-1 mTorr-1. The second, a vibrational quantum number swapping collision that effectively transfers population between the A and E symmetry species and thereby transcends the spin statistic selection rule, has a rate of 6.6 ±0.7 ms -1 mTorr-1, about 1.4 gas kinetic collisions. The numerical simulations and these rates, along with previous measurements of the ΔJ= ±1 rate and vibrational decay rates, provide an accurate characterization for a large body of varied experimental data. © 1989 American Institute of Physics.
Everitt, HO; De Lucia, FC
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