Abstract
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.
| Original language | American English |
|---|---|
| Pages (from-to) | 3380-3389 |
| Number of pages | 10 |
| Journal | Journal of Physical Chemistry A |
| Volume | 120 |
| Issue number | 19 |
| DOIs | |
| State | Published - 19 May 2016 |
Bibliographical note
Funding Information:^^Hebrew University Hebrew University was supported under the auspices of the Saerree K. and Louis P. Fiedler Chair in chemistry (R.B.G.). The research at the University of Helsinki was supported by the Academy of Finland through the FiDiPro program and grants No. 1139105 and No. 1277993. E.O.P acknowledges support from the National Science Foundation, Grant No. CHE-1414466.
Publisher Copyright:
© 2016 American Chemical Society.