Infrared Spectrum of Toluene: Comparison of Anharmonic Isolated-Molecule Calculations and Experiments in Liquid Phase and in a Ne Matrix.
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.
Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University , Jerusalem 91904, Israel.
Roie
R
Knaanie
Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University , Jerusalem 91904, Israel.|Department of Physical Chemistry, University of Chemistry and Technology , Prague 16628, Czech Republic.
Jiří
J
Šebek
Department of Chemistry, University of Helsinki , P.O. Box 55, FI-00014 Helsinki, Finland.
Masashi
M
Tsuge
Department of Chemistry, University of Helsinki , P.O. Box 55, FI-00014 Helsinki, Finland.
Nanna
N
Myllys
Department of Chemistry, University of Helsinki , P.O. Box 55, FI-00014 Helsinki, Finland.
Leonid
L
Khriachtchev
Department of Chemistry, University of Helsinki , P.O. Box 55, FI-00014 Helsinki, Finland.
Markku
M
Räsänen
Department of Chemistry, University of California , Irvine, California 92697, United States.
Brian
B
Albee
Department of Chemistry, University of California , Irvine, California 92697, United States.
Eric O
EO
Potma
Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University , Jerusalem 91904, Israel.|Department of Chemistry, University of Helsinki , P.O. Box 55, FI-00014 Helsinki, Finland.|Department of Chemistry, University of California , Irvine, California 92697, United States.
R Benny
RB
Gerber