Infrared Spectrum of Toluene: Comparison of Anharmonic Isolated-Molecule Calculations and Experiments in Liquid Phase and in a Ne Matrix

Roie Knaanie, Jiří Šebek, Masashi Tsuge, Nanna Myllys, Leonid Khriachtchev, Markku Räsänen, Brian Albee, Eric O. Potma, R. Benny Gerber*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

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 languageAmerican English
Pages (from-to)3380-3389
Number of pages10
JournalJournal of Physical Chemistry A
Volume120
Issue number19
DOIs
StatePublished - 19 May 2016

Bibliographical note

Publisher Copyright:
© 2016 American Chemical Society.

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