Direct observation of vibrational energy dispersal via methyl torsions
| Autor: | Laura E. Whalley, Adrian M. Gardner, William D. Tuttle, Timothy G. Wright |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Physics
010304 chemical physics Torsion (mechanics) General Chemistry Dissipation 010402 general chemistry 01 natural sciences Molecular physics Fluorescence Spectral line 0104 chemical sciences 3. Good health Vibration chemistry.chemical_compound chemistry 0103 physical sciences Density of states Physics::Chemical Physics Rotational–vibrational coupling Methyl group |
| Zdroj: | Chemical Science. 9:2270-2283 |
| ISSN: | 2041-6539 2041-6520 |
| DOI: | 10.1039/c7sc05309f |
| Popis: | Explicit evidence for the role of methyl rotor levels in promoting energy dispersal is reported. A set of coupled zero-order vibration/vibration-torsion (vibtor) levels in the S1 state of para-fluorotoluene (pFT) are investigated. Two-dimensional laser-induced fluorescence (2D-LIF) and two-dimensional zero-kinetic-energy (2D-ZEKE) spectra are reported, and the assignment of the main features in both sets of spectra reveals that the methyl torsion is instrumental in providing a route for coupling between vibrational levels of different symmetry classes. We find that there is very localized, and selective, dissipation of energy via doorway states, and that, in addition to an increase in the density of states, a critical role of the methyl group is a relaxation of symmetry constraints compared to direct vibrational coupling. |
| Databáze: | OpenAIRE |
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