Ab initio anharmonic analysis of complex vibrational spectra of phenylacetylene and fluorophenylacetylenes in the acetylenic and aromatic C-H stretching region.
| Autor: | Singh S; Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India., Huang QR; Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan., Tan JA; Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan., Kuo JL; Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan., Patwari GN; Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. |
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| Jazyk: | angličtina |
| Zdroj: | The Journal of chemical physics [J Chem Phys] 2023 Sep 14; Vol. 159 (10). |
| DOI: | 10.1063/5.0160700 |
| Abstrakt: | Vibrational spectra in the acetylenic and aromatic C-H stretching regions of phenylacetylene and fluorophenylacetylenes, viz., 2-fluorophenylacetylene, 3-fluorophenylacetylene, and 4-fluorophenylacetylene, were measured using the IR-UV double resonance spectroscopic method. The spectra, in both acetylenic and aromatic C-H stretching regions, were complex exhibiting multiple bands. Ab-initio anharmonic calculations with quartic potential using B97D3/6-311++G(d,p) and vibrational configuration interaction were able to capture all important spectral features in both the regions of the experimentally observed spectra for all four molecules considered in the present work. Interestingly, for phenylacetylene, the spectrum in the acetylenic C-H stretching region emerges due to anharmonic coupling of modes localized on the acetylenic moiety along with the other ring modes, which also involve displacements on the acetylenic group, which is in contrast to what has been proposed and propagated in the literature. In general, this coupling scheme is invariant to the fluorine atom substitution. For the aromatic C-H stretching region, the observed spectrum emerges due to the coupling of the C-H stretching with C-C stretching and C-H in-plane bending modes. (© 2023 Author(s). Published under an exclusive license by AIP Publishing.) |
| Databáze: | MEDLINE |
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