In this paper we present the results of an experimental study of the absorption spectrum of benzene and deuterated benzenes in solid Ar, Kr, Xe, and N2 in the spectral region 2800-1700 Å, with special reference to the 2100- and to the 1850-Å transitions. Our main results are: (a) On the basis of the observed vibrational structure the second excited singlet state of the benzene molecule is assigned to the 1A12- →1B1v rather than to the 1A 1g→1E2g excitation. (b) Theoretical calculations of the dynamic electronic-vibrational coupling between the 1B1x and the 1E1u states support the 1B1x assignment of the 2100-Å transition. (c) The vibrational structure of the 1850-Å 1A1g→ 1E1u transition was resolved. (d) No experimental evidence for Jahn-Teller coupling in the π→π* 1E 1u state was observed, in agreement with theoretical analysis. (e) Information on site splittings for the higher π→π* excitation of benzene in rare-gas solids has accumulated. (f) Analysis of matrix shifts for the 1A1g→1B1u and 1A1g→1E1u transitions indicates that the "solvent effect" is dominated by dispersion interactions. (g) Information on deuteration effects on the 1B1u and 1E1u energy levels was obtained. (h) Qualitative information on intramolecular radiationless decay in the two higher π→π* excited states of the benzene molecule has been inferred from the linewidths in the absorption spectrum.
|Number of pages||15|
|Journal||The Journal of Chemical Physics|
|State||Published - 1970|