Inelastic scattering, measurement methods

Infrared and Raman spectroscopy are related by the fact that both permit the detection of bond vibrations. Like IR spectroscopy, the spectral bands are reported in cnT1. An important difference is that the wavelength and intensity of inelastically scattered light is measured in the Raman spectroscopic method. The Raman effect causes the scattered radiation to shift according to the energies of molecular vibrations. Although Raman spectroscopy involves a physical principle different from that in IR spectroscopy, the two techniques are complementary. 

Table II Space- and Time-Resolved Measurements from Inelastic Light Scattering. All methods are suitable for nonequilibrium conditions. Here, RS refers to Raman scattering, CARS to coherent anti-Stokes Raman spectroscopy, and RIKES to Raman-induced Kerr effect.

This review has summarize the applications of neutron inelastic scattering to the study of pol3uners. The technique has proven useful for measuring and characterizii low-frequency intramolecular and inter-molecular vibrations, particularly for three systems, such as polyethylene and the n-paraffins, for which theoretical calculations of phase-frequency relations are available. More calculations of this type, and extension of them to include the effects of departures of chain conformations from their ideal transplanar or helical configurations, are needed for an optimum application of the method. 

In the apparatus of the second type, in which the diffraction pattern is observed on a fluorescent screen, the inelastically scattered electrons are excluded by a grid placed between the inner grid and the fluorescent screen (5). This method is being used in certain qualitative investigations in this laboratory but it does not furnish quantitative measurements of intensity which compare with those of the electrical method. 

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