High inverse Raman spectrum

Figure 6.1-26 High resolution inverse Raman spectrum of the 2-branch of CH3D between 2194 and 2200 cm Upper traces observed, lower traces calculated spectra (Bennejo et a)., 1990).

Figure 15 High resolution inverse Raman Spectrum of the V2 Q-branch of CH3D between 2194 and 2200 cm Upper traces Observed, lower traces calculated spectra. Reproduced by permission of John Wiley Sons from Bermejo D, Santos J, Cancio P etal (1990) High-resolution quasicontinuous wave inverse Raman spectrometer. Spectrum of CH3D in the C-D stretching region. Journal of Raman Spectroscopy 21 197-201.

With the available high-power lasers the nonlinear response of matter to incident radiation can be studied. We will briefly discuss as examples the stimulated Raman effect, which can be used to investigate induced vibrational and rotational Raman spectra in solids, liquids or gases, and the inverse Raman effect which allows rapid analysis of a total Raman spectrum. A review of the applications of these and other nonlinear effects to Raman spectroscopy has been given by Schrotter2i4)... 

An example for high-resolution IRS is given in Fig. 6.1-26, where the uj 0-branch of CH3D is displayed. This spectrum has been recorded with the quasi-cw inverse Raman spectrometer developed by Bermejo et al. (1990) whose. schematic arrangement is shown in Fig. 3.6-15 and described in Sec. 3.6.2.3. It represents a Doppler-limited spectrum of the C-D stretching band. The authors were able to assign the observed transitions by performing a theoretical fit to the observed data which allowed them to refine some of the rotational-vibrational constants. 

D Bermejo, J Santos, P Cancio, JL Domenech, C Domingo, JM Orza, J Ortigoso, R Escribano. High-resolution quasi-continuous wave inverse Raman spectrometer. Spectrum of CH3D in the C —D stretching region. J Raman Spectrosc 21 197-201, 1990. 

Bermejo D, Santos J, Cancio P etal (1990) High-resolution quasicontinuous wave inverse Raman spectrometer. Spectrum of CHjD in the C-D stretching region. Journal of Raman Spectroscopy 21 197-201. 

All iy(C=C) vibrations give rise to sharp and narrow Raman bands of high intensity. IR spectra, on the other hand, frequently exhibit comparatively weak C=C vibrations. A symmetrical substitution in trans position introduces a center of inversion at the center of the C=C bond due to the rule of mutual exclusion (Sec. 2.7.3.4) the C=C vibration must then be forbidden in the infrared spectrum. 

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