Vibrational spectroscopy benzene

Iachello, F., and Oss, S. (1993b), Vibrational spectroscopy and intramolecular relaxation of benzene, 7. Chem. Phys. 99, 7337. 

Reddy, K. V., Heller, D. F., and Berry, M. J. (1982), Highly Vibrationally Excited Benzene Overtone Spectroscopy and Intramolecular Dynamics of CsH6, C6D6, and Partially Deuterated or Substituted Benzenes, J. Chem. Phys. 76, 2814. 

Historically, the cyclic structure of benzene with symmetry, as shown in Fig. 7.3.15, was deduced by enumerating the derivatives formed in the mono-, di-, tri-substitution reactions of benzene. The structure can also be established directly using physical methods such as X-ray and neutron diffraction, NMR, and vibrational spectroscopy. We now discuss the infrared and Raman spectral data of benzene. 

Venturo VA, Felker PM. Nonlinear Raman spectroscopy of ground-state intermolecular vibrations in benzene complexes. J Phys Chem 1993 97 4882-4886. 

The symmetry of many molecules and especially of crystals is immediately obvious. Benzene has a six-fold symmetry axis and is planar, buckminsterfullerene (or just fullerene or footballene) contains 60 carbon atoms, regularly arranged in six- and five-membered rings with the same symmetry (point group //,) as that of the Platonic bodies pentagon dodecahedron and icosahedron (Fig. 2.7-1). Most crystals exhibit macroscopically visible symmetry axes and planes. In order to utilize the symmetry of molecules and crystals for vibrational spectroscopy, the symmetry properties have to be defined conveniently. 

Numerous papers deal with the vibrational spectroscopy of charge-transfer complexes. Only a few recent papers are mentioned here because they deal with systems for which the possibility of performing deeper theoretical investigations in near future is very promising. The infrared spectra of the following complexes were studied in nitrogen (and argon) matrices H O... COj (for an ab initio study see Ref. ) HjN. .. CO/ , H,N. .. Cl/ , H,(). .. H O , benzene. .. Cl, Br, IC1 , benzene. .. I/ , H S. .. CH,O . 

Vibrational dispersion is, for vibrations of the same type, the variation of the relative phase of atomic displacements with their frequency. Although it is a well known effect in molecular spectroscopy it is not usually presented as such. Rather there is an emphasis on treating each vibration individually and the deep similarities between vibrations of the same type are often obscured. Dispersion in molecules is normally seen in its discrete form and the effect of continuous dispersion is only observed in the spectroscopy of polymers ( 10.1.1.1). The connection between the discrete and continuous forms is most easily seen by considering the vibrations of molecules composed of simple chemical motifs repeated several-fold. We have chosen to demonstrate this with the highest frequency vibrations in benzene, the stretches of the six C-H repeat units. 

The hydrogenation is catalysed by nickel and other transition metals. Vibrational spectroscopy (infrared, HREELS, INS) has been applied to determining the orientation and binding of benzene on the catalyst surface. We suimnarise INS studies of benzene, adsorbed benzene and model complexes. The intensities and frequencies of the vibrational modes are computed by the Wilson GF method. The benzene molecule... 

B.E. Koel and G.A. Somoijai. Vibrational Spectroscopy Using HREELS of Benzene Adsorbed on the Rh(lll) Crystal Surface. J. Electron Spectrosc. Relat. Phenom. 29 287 (1983). 

A second, nontrivial example is benzene, C Hg. We address its complete vibrational spectroscopy in Section III.C.2. However, we can study the manifold of CH stretching modes in exactly the same way as done for the XFg molecule. The benzene molecule possesses six equivalent CH oscillators attached to the carbon ring, which will be neglected at... 

Figure 4.10 NIR spectrum of benzene (cf. SAQ 4.7). From Weyer, L. G. and Lo, S. C., Spectra-Structure Correlations in the Near-Infrared , in Handbook of Vibrational Spectroscopy, Vol. 3, Chalmers, J. M. and Griffiths, P. R. (Eds), pp. 1817-1837. Copyright 2002. John Wiley Sons Limited. Reproduced with permission.

Two numbering schemes for vibrational modes of benzene are in current use. That of Wilson is adopted in the present discussion because it has become firmly entrenched in the literature on electronic and vibrational spectroscopy of benzene. A majority of papers use this system rather than the more modern convention used in Herzberg s discussions. The numbering of the two systems is related in Table II. 

Dewar-benzene and benzvalene have been studied and all the fundamental vibrations of both benzene isomers have been assigned. Both molecules show abnormal C=C stretch vibrations. Dewar-benzene has also been studied using photoelectron spectroscopy as a part of the homologous series (3). Band assignments have been... 

Figure 2 Far-IR spectra of an 0.2 M iodine solution in benzene. The upper diagram shows the absorption coefficient and the lower diagram the infrared spectral density Uriy) as calculated according to Eq. (6) see text. [From M Besnard. Chemical kinetics and vibrational spectroscopy An analysis of weak charge transfer complexing reactions. In Molecular Liquids New Perspectives in Physics and Chemistry, JJC Teixeira-Dias, ed. Dordrecht Kluwer Academic, 1992, p 469. Reproduced with kind permission from Kluwer Academic Publishers.]...

BratUe KM, Khewer CJ, Somoijai GA (2006) Stmcture effects of benzene hydrogenation studied with sum frequency generation vibrational spectroscopy and kinetics on Pt(lll) and Pt(lOO) single-crystal surfaces. J Phys Chem B 110 17925-17930... 

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