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Abstract

We show that the intermediate scattering function \(S_n(q,t)\) for neutron scattering (ns) can be expanded naturely with respect to a set of molecular correlation functions that give a complete description of the translational and orientational two-point correlations in the liquid. The general properties of this expansion are discussed with special focus on the \(q\)-dependence and hints for a (partial) determination of the molecular correlation functions from neutron scattering results are given. The resulting representation of the static structure factor \(S_n(q)\) is studied in detail for a model system using data from a molecular dynamics simulation of a supercooled liquid of rigid diatomic molecules. The comparison between the exact result for \(S_n(q)\) and different approximations that result from a truncation of the series representation demonstrates its good convergence for the given model system. On the other hand it shows explicitly that the coupling between translational (TDOF) and orientational degrees of freedom (ODOF) of each molecule and rotational motion of different molecules can not be neglected in the supercooled regime.Further we report the existence of a prepeak in the ns-static structure factor of the examined fragile glassformer, demonstrating that prepeaks can occur even in the most simple molecular liquids. Besides examining the dependence of the prepeak on the scattering length and the temperature we use the expansion of \(S_n(q)\) into molecular correlation functions to point out intermediate range orientational order as its principle origin.

Details

1009240
Title
Neutron scattering and molecular correlations in a supercooled liquid
Publication title
arXiv.org; Ithaca
Publication year
1999
Publication date
Feb 4, 1999
Section
Condensed Matter
Publisher
Cornell University Library, arXiv.org
Source
arXiv.org
Place of publication
Ithaca
Country of publication
United States
University/institution
Cornell University Library arXiv.org
e-ISSN
2331-8422
Source type
Working Paper
Language of publication
English
Document type
Working Paper
Publication history
 
 
Online publication date
2009-10-31
Milestone dates
1999-02-04 (Submission v1)
Publication history
 
 
   First posting date
31 Oct 2009
ProQuest document ID
2088210591
Document URL
https://www.proquest.com/working-papers/neutron-scattering-molecular-correlations/docview/2088210591/se-2?accountid=208611
Full text outside of ProQuest
Copyright
© 1999. This work is published under https://arxiv.org/licenses/assumed-1991-2003/license.html (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.
Last updated
2019-04-17
Database
ProQuest One Academic