Overtone benzene

Wyatt R E, lung C and Leforestier C 1992 Quantum dynamics of overtone relaxation in benzene. II. Sixteen-mode model for relaxation from CH(v = 3) J. Chem. Phys. 97 3477-86... 

Minehardt T A, Adcock J D and Wyatt R E 1999 Quantum dynamics of overtone relaxation in 30-mode benzene a time-dependent local mode analysis for CH(v = 2) J. Chem. Phys. 110 3326-34... 

C-C-, in benzene rings Two sharp, strong peaks near 1500 and 1600 cm"1, a series of weak peaks (called overtones) between 1600 and 2000 cm"1, the latter in the case of a mono-substituted benzene ring... 

Figure 6.9 Observed opto-thermal spectrum of the Avcw = 3 overtone of benzene (points with error bars) and a stick spectrum calculated by means of the algebraic theory. Labels indicate the most important states involved in borrowing intensity from the CH overtone. Adapted from Bassi et al. (1993).

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. 

Overtone bands of mono-substituted benzene ring... 

Fig. 1. First overtone band of the surface OH-groups of alumosilicagel, immersed into carbon tetrachloride (1), chlorobenzene (2), benzene (3), toluene (4) and acetone (5). (From top to bottom)...

The characteristic pattern of overtone bands and combination vibrations between 2000 and 1660 cm in the IR spectra of alkyl substituted benzene derivatives as well as the out-of-plane deformation vibrations of the hydrogen atoms in the IR spectra are frequently less reliable as indicators of the substitution pattern, especially in the presence of polar substituents, in which case their position tends to shift, and they often overlap with bands of substituents. 

The density of states is approximately given by the number of ways of distributing A over the normal modes of vibration. Because of many low-frequency modes, the number of these overtones and combinations is enormous there are as many as 3 x 10 states per cm in the S,-T, case (A = 8,500 cm ) of benzene with 30 normal modes of vibration. 

We will conclude this section by mentioning several other recent studies which have employed AI selection procedures. Colbert and Sibert (18) used an AI selection scheme in their investigation of the OH (v = 4) overtone in HOOH. Zhang and Marcus (19) have developed a sophisticated AI selection scheme for use in their studies of the CH(v) benzene overtones. In their studies of overtone relaxation from the acetylenic CH stretch in molecules of the type (CH3)3C—CC—H, Stuchebrukhov and Marcus (4) have used a performance indicator similar to PI4 described above. The best-incomplete paths search algorithm with essentially PI5 was used by lung and Leforestier (20,21) for their studies of the overtone spectra and IVR in CD3H (more about this in Sec. III). 

A very demanding application of the computational methods discussed in Section II concerns the overtone spectroscopy and dynamics of energy flow in benzene. This section... 

In more recent times, during the mid-1970s, Albrecht and co-workers developed the thermal lens technique and used it to study the absorption spectrum of liquid benzene (120-123). In important studies during the late 1970s and early 1980s, Berry and coworkers recorded v = 1 to 9 overtone spectra of room temperature gas phase benzene using the intracavity cw dye laser technique with optoacoustic detection (124). They reported broad absorption features for v = 3, the roughly 100-cm 1 FWHM asymmetric absorption feature had a broad shoulder on the red side of the main feature. 

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