Intramolecular vibrational dynamics of propyne and its derivatives: The role of vibrational-rotational mixing
The dynamics of intramolecular vibrational energy redistribution from the initially excited {nu}{sub HC} mode in the propyne molecule (H-C{identical_to}C-CH{sub 3}), as well as in three its derivatives that are obtained by replacing one of the hydrogen atoms of the methyl group with the chlorine atom (propargylchloride), the OH radical (propargyl alcohol), or with the NH{sub 2} radical (propargylamine), has been studied. Probing was performed by anti-Stokes spontaneous Raman scattering. The measured values of the deexcitation rate W of the {nu}{sub HC} mode lie in the range 10{sup 9}-10{sup 10} s{sup -1}. A significant feature of the dynamics-an incomplete energy redistribution from the {nu}{sub HC} mode-is especially clearly pronounced for the H-C{identical_to}C-CH{sub 3} and H-C{identical_to}C-CH{sub 2}Cl molecules, for which the values of the relative level {sigma} of the residual energy in the {nu}{sub HC} mode are approximately equal to 0.54 and 0.25, respectively. A theoretical analysis performed made it possible to relate the parameters W and {sigma}, on the one hand, and the density {rho} of the so-called bath states, which are responsible for the vibrational energy redistribution, on the other hand. It is shown that, for all the four molecules considered, the required values of {rho} can be accounted for solely by a strong vibrational-rotational mixing in the bath, as a result of which the projection of the total angular momentum onto the axis of the molecule ceases to be 'good' quantum number.
- OSTI ID:
- 21075634
- Journal Information:
- Journal of Experimental and Theoretical Physics, Journal Name: Journal of Experimental and Theoretical Physics Journal Issue: 1 Vol. 106; ISSN JTPHES; ISSN 1063-7761
- Country of Publication:
- United States
- Language:
- English
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