Infrared Spectrum of Toluene: Comparison of Anharmonic Isolated-Molecule Calculations and Experiments in Liquid Phase and in a Ne Matrix
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- 作者：Roie Knaanie ; Jiří Šebek ; Masashi Tsuge ; Nanna Myllys ; Leonid Khriachtchev ; Markku Räsänen ; Brian Albee ; Eric O. Potma ; R. Benny Gerber
- 刊名：Journal of Physical Chemistry A
- 出版年：2016
- 出版时间：May 19, 2016
- 年：2016
- 卷：120
- 期：19
- 页码：3380-3389
- 全文大小：529K
- 年卷期：0
- ISSN：1520-5215
文摘
First-principles anharmonic calculations are carried out for the CH stretching vibrations of isolated toluene and compared with the experimental infrared spectra of isotopologues of toluene in a Ne matrix at 3 K and of liquid toluene at room temperature. The calculations use the vibrational self-consistent field method and the B3LYP potential surface. In general, good agreement is found between the calculations and experiments. However, the spectrum of toluene in a Ne matrix is more complicated than that predicted theoretically. This distinction is discussed in terms of matrix-site and resonance effects. Interestingly, the strongest peak in the CH stretching spectrum has similar widths in the liquid phase and in a Ne matrix, despite the very different temperatures. Implications of this observation to the broadening mechanism are discussed. Finally, our results show that the B3LYP potential offers a good description of the anharmonic CH stretching band in toluene, but a proper description of matrix-site and resonance effects remains a challenge.