Neutron inelastic scattering instruments

Hole Burning Spectroscopy, Methods Inelastic Neutron Scattering, Instrumentation... 

See also Inelastic Neutron Scattering, Applications Inelastic Neutron Scattering, Instrumentation Inorganic Compounds and Minerals Studied Using X-Ray Diffraction Materials Science Applications of X-Ray Diffraction Neutron Diffraction, Theory Powder X-Ray Diffraction, Applications Structure Refinement (Solid State Diffraction). 

See also ATR and Reflectance IR Spectroscopy, Applications High Resolution Electron Energy Loss Spectroscopy, Applications Inelastic Neutron Scattering, Applications Inelastic Neutron Scattering, Instrumentation IR Spectroscopy, Theory Raman and IR Microspectroscopy Surface-Enhanced Raman Scattering (SERS), Applications. 

See also Inelastic Neutron Scattering, Instrumentations IR Spectral Group Frequencies of Organic Compounds IR and Raman Spectroscopy of Inorganic, Coordination and Organometallic Compounds Scattering Theory Vibrational, Rotational and Raman Spectroscopy, Historical Perspective. 

Inelastic neutron scattering (INS) measurements have been successfully used to study dynamical phenomena such as molecular or lattice vibrations in pristine C60 [43] and a variety of fullerides [44-48]. When INS spectra are collected on instruments with a large energy window, it is possible to observe all phonon modes including the molecular vibrations and the generalised phonon density-of-states (GDOS) can be directly calculated. 

Fig. 13. Inelastic neutron-scattering spectra of Ar/MgO(100) at 10 K. (a) Experimental spectra at incident energy of 7 meV for a 1.16 layer (hexagonal structure) the vertical bars and the triangle represent experimental errors and the experimental broadening (reduced by a factor of 1/10), respectively (b) calculated spectrum for the hexagonal incommensurate structure after convoluting with the instrumental line shape of 0.3 meV at a neutron gain of 5 meV. Units are arbitrary and the basehne is shifted with respect to curve (a) (fiomRef 99).

On the instrumental side, most inelastic neutron scattering setups are capable of molecular spectroscopic experiments perhaps TOSCA, installed at the ISIS Pulsed Neutron and Muon Facility (UK), should be mentioned as it is dedicated to such studies (ISIS 2003). Data analysis most often includes quantum chemical calculations of the vibrational density of states, which are compared to experiment (see, e.g.. Line and Kearley 2000 Fernandez-Liencres et al. 2001). 

As already anticipated, a complementary experimental technique for deriving information on the dynamics (frequencies and vibrational amplitudes) of polymers or of materials in general is the use of inelastic neutron-scattering techniques (INS). After a long development time, during which experiments were difficult and provided limited information, the instruments in a few specialized centers recently began to provide detailed data covering the whole spectrum. Thus, we predict a renaissance of INS techniques for the studies of molecular and lattice dynamics. 

There are two broad classes of neutron scattering measurement. In diffraction measurements, the energy of the scattered radiation is not analyzed, so only the intensity versus Q is determined. Such measurements determine the structure of the sample. In a second class, the scattered energy is analyzed, so the intensity versus Q and h(0 is determined. This type of measurement is able to give structural and dynamic information about the sample, and is often called an inelastic measurement. In the special case where there are diffusive motions in the sample, which broaden the sharp incident spectrum, the term quasi-elastic is used. Neutron scattering instruments are optimized for one or the other of these types of measurement. 

In Fig. 18, the (701) direction corresponds to momentum transfer parallel to the dimer planes (Qy = Qz = 0). Elastic and inelastic incoherent scattering give the broad signal centered at Q = 0, hiding quantum interferences observed in Fig. 16. (With the SXD instrument, neutrons scattered with different final energies are not distinguished.)... 

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