Dynamic structure factor inelastic neutron scattering

Recently, the PDF method was extended to describe the local dynamics of disordered materials (Dmowski W, Vakhrushev SB, Jeong I-K, Hehlen M, Trouw F, Egami T (2006) Abstracts American conference on neutron scattering, St. Charles, IL, 18-22 June 2006, unpublished). The total PDF is obtained by the powder diffraction method so that S(Q) includes both elastic and inelastic intensities. To determine the dynamics we have to use an inelastic neutron scattering spectrometer and measure the dynamic structure factor, S(Q,a>), over a large Q and co space, and Fourier-transform along Q to obtain the dynamic PDF (DPDF). While the interpretation of the DPDF is a little... 

A. Pasquarello, J. Samthein R. Car (1998). Phys. Rev. B, 57, 14133-14140. Dynamic structure factor of vitreous silica from first principles Comparison to neutron-inelastic-scattering experiments. 

Inelastic neutron scattering is a technique that has been widely used both in the liquid and in the solid states to measure the stmcture and dynamics at small (that is, molecular) length scales. In an incoherent inelastic neutron-scattering experiment, the measured quantity is the self-dynamic structure factor Ss(Q, (o), which gives information, as in the liquid state, of the self-diSiision coefficient of the water molecules. Ss(Q, (o) is the Fourier transform of the intermediate self-scattering function Fg(Q, t), which is defined by... 

The most obvious experimental manifestations of interionic correlation are found in the Haven ratio (deduced from diffusion and conductivity measurement, see Chapter 4), in the static structure factor S(Q) (deduced from partial occupation factors measured by X-ray or neutron diffraction) and from the dynamical properties (S Q, co), quasi- and inelastic-neutron scattering, frequency dependent conductivity) and e(co) dielectric relaxation. 

Rg. 1. Dynamic structure factor 5(ik, various values off = fta .The solid curves are present kinetic model calculations the points are coherent neutron inelastic scattering data/ ... 

Dynamic structure factor S of (hexagonal) H2O ( H2O) ice (phase Ih), obtained from incoherent inelastic neutron scattering (Li 1996) vs. wave number v. Note the similarity of the above curve to results of conventional vibrational spectroscopic methods (IR, Raman)... 

Quasi-elastic Neutron Scattering. Coherent and incoherent inelastic neutron scattering are unique experimental techniques to characterize molecular motions on a time scale between 10 and 10 s. The continued development of high resolution inelastic scattering techniques in the past two decades (157-159) enables measurement of the dynamic structure factor S(Q, co) and the... 

In inelastic neutron scattering (INS) experiments, the dynamic structure factor S Q,o),T) is related to the dynamic susceptibility weighted with the detailed balance factor... 

According to Sect. 3.1, the structure factor S(q) affects the q-dependence of the apparent diffusion coefficient. The first study of the q-dependence of the diffusion coefficient was performed using inelastic neutron scattering [20]. The results demonstrated that the diffusion coefficient exhibits a minimum at a q-value where the scattered intensity shows a maximum in qualitative agreement with theory. Dynamic light scattering experiments on PSS in the concentration... 

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