Neutron diffusion

Those Warren-Cowley parameters have been determined in situ above the order-disorder transition temperature by diffuse neutron scattering. From these experimentally determined static correlations, the first nine effective pair interactions have been deduced using inverse Monte Carlo simulations. 

X-ray and diffuse neutron scattering and diffraction studies of PMN have been interpreted in terms of the spherical layer model of Vakhrushev et al. [25,26]. The Pb atom is not situated at the (000) position as it should be for an ideal perovskite lattice, but is distributed over a sphere of radius R around this position. 

We now wish to examine how the structure of the dressed macroion, as determined by our diffuse neutron scattering experiments, varies with applied uniaxial stress. The best data was obtained at c = 0.03 M, with r < 0.01, when the uniaxial pressure p was varied between 0 and 0.2 atm a single experiment conducted over two days on D16 gave clear ripples at different applied stresses, as described below. As in the experiments at c = 0.1 and 0.01 M described above, T and P were held constant at 10°C and 1 atm, respectively. The details of the experiment and the small-angle patterns observed are given in reference [4], Here we concentrate on how applied uniaxial pressure affects the higher g-rangc of the structure factors. 

We first used isotope substitution in diffuse neutron scattering measurements to determine the distribution of water molecules and counterions (n-butylammonium ions) around the clay layers in the gel state, and obtained a unique picture of a dressed macroion in solution. We obtained a structure in which the naked clay plate of 10 A thickness was extended out to about 35 A by layers of water molecules and counterions. The dressed macroion has exactly two layers of water molecules coating the clay layers these layers are 6 A thick on both sides, extending the effective clay plate out to 22 A, before any counterions at all are found. This is in direct contradiction to the Stem layer picture, widely held in colloid science, that... 

V. M.NieldandD. A. Keen, Diffuse Neutron Scattering from Crystalline Materials , Oxford University Press, 2000. 

Figure 6.4 (a) Single crystal diffuse neutron scattering data measured in the (orthorhombic) hOl plane of ice Ih and (b) RMC fit. 

Besnus et al. (1982) have performed magnetization, diffuse neutron scattering, 57Fe Mossbauer and NMR studies on these C15 Laves phase compounds over a wide range of composition. The Curie temperatures and average moments are reduced with increasing Mn content and it was concluded from the neutron and NMR data... 

Nelmes RJ, Kuhs WF, Howard CJ, Tibballs JE, Ryan TW (1985) J Phys C Solid State Phys 18 L711 Nield VM, Keen DA (2001) Diffuse neutron scattering. Clarendon, Oxford... 

Section 1 of the work can be considered as an introduction to elementary polymer physics. I have felt it necessary to give a brief account of the basis of the subject to make the review self-contained. Basic terms and heuristic models of polymer science are described in this Section. The subsequent sections contain an exposition of the mesoscopic theory itself, while in Sects. 5, 6 and 7 consequences of the theory when compared to experimental data on diffusion, neutron scattering, viscoelasticity and optical anisotropy are discussed. 

Solutions, melts rheology, diffusion, neutron scattering... 

---