Topic

# Neutron scattering

About: Neutron scattering is a research topic. Over the lifetime, 24728 publications have been published within this topic receiving 477556 citations.

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TL;DR: The application of thermal neutron scattering to the study of the structure and dynamics of condensed matter requires a knowledge of the scattering lengths and the corresponding scattering and absorption cross sections of the elements as discussed by the authors.

Abstract: The application of thermal neutron scattering to the study of the structure and dynamics of condensed matter requires a knowledge of the scattering lengths and the corresponding scattering and absorption cross sections of the elements. Ln some cases, values for the individual isotopes are needed as well. This information is required to obtain an absolute normalization ofthe scatteredneutron distributions, tocalculate unit-cell structure factors in neutron crystallography, and to correct for effects such as absorption, self-shielding, extinction, multiple scattering, incoherent scattering, and detector efficiency.

3,077 citations

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TL;DR: The characteristic features of alpha and beta relaxation in the supercooled state of non-network forming liquids and polymers are reviewed in this paper, where a crossover temperature Tc, located above the calorimetric glass transition temperature Tg, where the transport properties change from those typical for a strongly coupled liquid to those characteristic for a glass.

Abstract: The characteristic features of alpha - and beta - relaxation in the supercooled state of nonnetwork forming liquids and polymers are reviewed. Particular emphasis is put on properties observed recently by neutron scattering and molecular dynamics studies within the mesoscopic time region. The data indicate the existence of a crossover temperature Tc, located above the calorimetric glass transition temperature Tg, where the transport properties change from those typical for a strongly coupled liquid to those characteristic for a glass. Near Tc the alpha -process is specified by Debye-Waller factor anomalies, power law divergences of the relaxation scale and a crossover from alpha -scale universality to decoupling of the various relaxation processes. The beta -process is characterized by a complete absence of correlations between spatial and temporal motion and unconventional scaling laws. There appear two fractal time decay processes and two divergent time scales if the cross over temperature is approached. The results of the mode coupling theory for the supercooled liquid dynamics are reviewed and shown to give a unified and partly quantitative description of the Tc anomalies.

2,296 citations

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TL;DR: In this paper, a natural time-dependent generalization for the well-known pair distribution function $g(mathrm{r})$ of systems of interacting particles is given, which gives rise to a very simple and entirely general expression for the angular and energy distribution of Born approximation scattering by the system.

Abstract: A natural time-dependent generalization is given for the well-known pair distribution function $g(\mathrm{r})$ of systems of interacting particles. The pair distribution in space and time thus defined, denoted by $G(\mathrm{r}, t)$, gives rise to a very simple and entirely general expression for the angular and energy distribution of Born approximation scattering by the system. This expression is the natural extension of the familiar Zernike-Prins formula to scattering in which the energy transfers are not negligible compared to the energy of the scattered particle. It is therefore of particular interest for scattering of slow neutrons by general systems of interacting particles: $G$ is then the proper function in terms of which to analyze the scattering data.After defining the $G$ function and expressing the Born approximation scattering formula in terms of it, the paper studies its general properties and indicates its role for neutron scattering. The qualitative behavior of $G$ for liquids and dense gases is then described and the long-range part exhibited by the function near the critical point is calculated. The explicit expression of $G$ for crystals and for ideal quantum gases is briefly derived and discussed.

2,015 citations

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31 Dec 1987

TL;DR: The use of elastic scattering is used in various branches of science and technology, including condensed matter physics, molecular biology and biophysics, polymer science, and metallurgy as mentioned in this paper.

Abstract: Small-angle scattering of X rays and neutrons is a widely used diffraction method for studying the structure of matter. This method of elastic scattering is used in various branches of science and technology, includ ing condensed matter physics, molecular biology and biophysics, polymer science, and metallurgy. Many small-angle scattering studies are of value for pure science and practical applications. It is well known that the most general and informative method for investigating the spatial structure of matter is based on wave-diffraction phenomena. In diffraction experiments a primary beam of radiation influences a studied object, and the scattering pattern is analyzed. In principle, this analysis allows one to obtain information on the structure of a substance with a spatial resolution determined by the wavelength of the radiation. Diffraction methods are used for studying matter on all scales, from elementary particles to macro-objects. The use of X rays, neutrons, and electron beams, with wavelengths of about 1 A, permits the study of the condensed state of matter, solids and liquids, down to atomic resolution. Determination of the atomic structure of crystals, i.e., the arrangement of atoms in a unit cell, is an important example of this line of investigation."

1,923 citations