Jump to ContentJump to Main Navigation
Quasielastic Neutron Scattering and Solid State Diffusion$
Users without a subscription are not able to see the full content.

Rolf Hempelmann

Print publication date: 2000

Print ISBN-13: 9780198517436

Published to Oxford Scholarship Online: January 2010

DOI: 10.1093/acprof:oso/9780198517436.001.0001

Show Summary Details
Page of

PRINTED FROM OXFORD SCHOLARSHIP ONLINE (www.oxfordscholarship.com). (c) Copyright Oxford University Press, 2019. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a monograph in OSO for personal use (for details see www.oxfordscholarship.com/page/privacy-policy).date: 21 May 2019

Incoherent quasielastic neutron scattering

Incoherent quasielastic neutron scattering

(p.96) 5 Incoherent quasielastic neutron scattering
Quasielastic Neutron Scattering and Solid State Diffusion

Rolf Hempelmann

Oxford University Press

In the case of spatially limited jump diffusion, the incoherent scattering function consists of an elastic and a quasielastic part, and the fraction of elastic intensity is called the incoherent structure factor, EISF. This chapter evaluates different scenarios and the corresponding EISFs. Long range translational diffusion gives rise to quasielastic scattering consisting of a single Lorentzian with a linewidth proportional to Q2. The Chudley–Elliott model for lattice gases describes translational jump diffusion in Bravais lattices. QENS from translational jump diffusion on lattices with all sites equivalent consists of a set of Lorentzians. Even more complex is QENS from diffusion over energetically different sites. The system of rate equation is expressed in terms of a jump matrix, but this matrix is not hermitean. The resulting eigenvalues are the linewidths of the Lorentzians, whereas from the eigenvectors the intensity of the Lorentzians can be calculated. This full power of QENS can only be realized on the basis of direction-dependent measurements on single-crystalline samples. A completely different approach is the so-called two-state model which applies for disordered systems and which is also derived in full detail.

Keywords:   single Lorentzian, translational jump diffusion, Chudley–Elliott model, two-state model, disordered systems

Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.

Please, subscribe or login to access full text content.

If you think you should have access to this title, please contact your librarian.

To troubleshoot, please check our FAQs , and if you can't find the answer there, please contact us .