| Autor: |
Vasilatou, K., Michaud, J. M., Baykusheva, D., Grassi, G., Merkt, F. |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 8/14/2014, Vol. 141 Issue 6, p1-13, 13p, 4 Diagrams, 5 Charts, 6 Graphs |
| Abstrakt: |
The cyclopropene radical cation (c-C3H+4) is an important but poorly characterized three-memberedring hydrocarbon. We report on a measurement of the high-resolution photoelectron and photoionization spectra of cyclopropene and several deuterated isotopomers, from which we have determined the rovibrational energy level structure of the X+ ²B2 ground electronic state of c-C3H+4 at low energies for the first time. The synthesis of the partially deuterated isotopomers always resulted in mixtures of several isotopomers, differing in their number of D atoms and in the location of these atoms, so that the photoelectron spectra of deuterated samples are superpositions of the spectra of several isotopomers. The rotationally resolved spectra indicate a C2v-symmetric R0 structure for the ground electronic state of c-C3H+4. Two vibrational modes of c-C3H+4 are found to have vibrational wave numbers below 300 cm-1, which is surprising for such a small cyclic hydrocarbon. The analysis of the isotopic shifts of the vibrational levels enabled the assignment of the lowest-frequency mode (fundamental wave number of ≈110 cm-1 in c-C3H+4 ) to the CH2 torsional mode (v+8, A2 symmetry) and of the second-lowest-frequency mode (≈210 cm-1 in c-C3H+4) to a mode combining a CH out-of-plane with a CH2 rocking motion (v+15, B2 symmetry). The potential energy along the CH2 torsional coordinate is flat near the equilibrium structure and leads to a pronounced anharmonicity. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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