Publication
Title
Monte Carlo simulations of dielectric relaxation in Na-mordenites
Author
Abstract
The chemical composition of zeolites is defined by the average ratio between the number of 4-coordinated Si and Al atoms of the lattice (ratio Si/Al). Each Al atom adds a net negative charge to the otherwise SiO2 lattice which is counterbalanced by an extra-framework mobile cation. These counter-ions are responsible for the major polarization of the material at low frequencies (10(6) Hz). The nature, localization and diffusion of these cations depend on the Si/Al ratio and influence the catalytic properties of the material. Here, we present a joint theory-experiment study of these properties at the atomic level. The thermally stimulated depolarization current (TSDC) of Na-mordenites is measured for increasing Si/Al ratios. The analysis of these dielectric relaxation data leads to activation energy barriers for the Na+ "jumps" responsible for the polarization change. Using semi-empirical inter-atomic potentials and Monte Carlo algorithms we propose a possible mechanism for the cation motions occurring in TSDC experiments. (C) 2001 Elsevier Science B.V. All rights reserved.
Language
English
Source (journal)
Computational materials science
Publication
2001
ISSN
0927-0256
Volume/pages
22:1-2(2001), p. 106-111
ISI
000171255400019
Full text (Publisher's DOI)
Full text (publisher's version - intranet only)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 29.02.2012
Last edited 14.07.2017
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