Raman spectroscopy incident photon

Special Raman Spectroscopies. The weakness of Raman scattering results typically in the conversion of no more than 10 of the incident laser photons into a usable signal, limiting the sensitivity of conventional spontaneous Raman spectroscopy. This situation can be improved using alternative approaches (8,215,216). 

A Raman spectrum is a plot of light intensity versus photon energy. In the vibrational spectroscopy it is usual to express the photon energy by the wavenumbers, defined as v = 1/A. In the Raman spectroscopy the use of absolute wavenumbers would be impractical, because the wavelength and, with that, the absolute wavenumber of each obtained Raman bands must always depend on the wavenumber of the incident light vq. However, only the... 

Fig. 3.8. Dielectric band-pass filter used for the enhancement of signals in transmission Raman spectroscopy and a schematic illustration of the shift of the design wavelength with the angle of photon incidence...

Nafie (1992) has given a review about the latest VOA instrumentation. Until 1988, the only measured form of ROA was incident circular polarisation (ICP) ROA, but as the process observed in Raman spectroscopy is a two-photon process, there are four possibilities for measuring Raman optical activity. ICP ROA is the unpolarized measurement of the Raman radiation emitted upon excitation with alternating right and left circularly polarized light. It is shown in Fig. 6.3-12, following the sketches of Nafie. As the first of the other possibilities scattered circular polarisation (SCP) ROA was measured. This... 

Single-electronic-state (SES) limit The Raman spectroscopy in SES limit is where the incident photon energy is very close to, or falls within, the absorption band of an excited electronic state of a molecule, and the resulting Resonance Raman (RR) scattering is dominated by the properties of this resonant electronic state. 

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