Pucker modes

In cyclohexane there are three puckering modes described by the generalized coordinates q2, q3, and . Cremer and Pople [1975a,b] introduced the amplitude Q q2 = Q sin 0, q3 = Q cos 0) to portray the set of conformers in spherical coordinates (Figure 8.9). The axial conformer C (6 = 0°, 180°) has a chair-like shape. Transverse displace-... 

For an AX3 planar molecule the symmetry is D3h. The puckering mode (Figure 7-5b) of A2 symmetry reduces it to C3v. In the C3v point group, the symmetry of this vibration is A . 

B. Lesyng and W. Saenger, Carbohydrate Res., 133,187 (1984). Influence of the Orientation of Hydroxyl Groups on the Puckering Modes of Furanoid Rings. 

FIGURE 1 Potential function and vibrational energy levels of the ring-puckering mode of silacyclobutane. (Reproduced by permission from Laurie and Lord. )... 

The vibrational energy of the puckering mode may be calculated from the one-dimensional wave equation... 

The value of the observation of such transitions is obvious. If the puckering mode is inactive or too weak to be observed directly in the far-infrared region or by Raman spectroscopy the barrier height can be determined from these transitions if they are detectable. Even if the puckering vibration can be studied directly, these transitions provide a check to the assignment of the directly observed transitions. Further-... 

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