Hyper-Raman light scattering

Hyper-Raman light scattering is that, unlike linear scattering (see Section 3.2.5), two photons with the frequency nj participate in the inelastic collision with the particle B(J). As a result, a molecule in the different eneigy state and one photon with the energy /ii are formed... 

At present, in spite of the well-known fact that the interaction of atoms and molecules leads to the changing of their multipole moments and (hyper)polariz-abilities [1-3], only the simple moments and polarizabilities of interacting molecules such as interaction-induced dipole moments and dipole polarizabilities have widely studied. Nevertheless, the induced dipole moments and polarizabilities play the important role in understanding the collision-induced absorption, collision-induced Rayleigh scattering or collision-induced Raman light scattering [4-9],... 

Cyvin, S. J., Rauch, J. E. and Decius, J. C. (1965) Theory of hyper-Raman effects (nonlinear inelastic light scattering) selection rules and depolarization ratios for the second-order polarizability. 

Raman scattering Infrared absorption Inelastic harmonic light scattering (Hyper-Raman) Neutron inelastic scattering Stimulated Raman scattering... 

Consider now the main features of light scattering by vibronic systems in a viscous medium. As in the preceding subsection, we exclude the Raman and hyper-Raman transitions between vibronic levels of different energy. Assume that ay = ay- and that only the ground vibronic degenerate state is populated, its wave functions belonging to the irreducible representation T. 

Hyper-Rayleigh and hyper-Raman scattering can be described by extending the linear relation (2.1) between the induced oscillating electric dipole moment and the electric field of the light wave to include higher-order terms ... 

Much more important for gas phase spectroscopy than the hyper-Raman effect are the various coherent Raman effects, so we shall develop the theory of coherent Raman scattering in rather more detail. The usual starting point is the bulk polarization of the medium expressed as a function of the electric field vectors of the various light waves present simultaneously in the medium (SI)... 

It is not in the scope of the present chapter to review all possible experimental setups for the various types of Raman scattering classical, microprobe, Fourier transform (FT), coherent anti-Stokes (CARS), surface enhanced (SERS), hyper (HRS), photo-acoustic (PARS), and so forth (see, e.g.. Refs. 29-31). A basic Raman-scattering instrument requires a laser-light source, an appropriate sample holder, a sample illumination optical unit, a scattered-light collection optical unit (these two may be combined in one system), a disperser (spectrometer) or an interferometer, a light detection unit, a recorder, and an appropriate microcomputer able to drive, control, and record all of the experimental parameters as well as the results and their processing. 

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