Monte Carlo and molecular dynamics simulation of argon clusters andn-alkanes in the confined regions of zeolites

Rajappa, Chitra and Bandyopadhyay, Sanjoy and Subramanian, Yashonath (1997) Monte Carlo and molecular dynamics simulation of argon clusters andn-alkanes in the confined regions of zeolites. In: Bulletin of Materials Science, 20 (6). pp. 845-878.

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Abstract

Geometry and energy of argon clusters confined in zeolite NaCaA are compared with those of free clusters. Results indicate the possible existence of magic numbers among the confined clusters. Spectra obtained from instantaneous normal mode analysis of free and confined clusters give a larger percentage of imaginary frequencies for the latter indicating that the confined cluster atoms populate the saddle points of the potential energy surface significantly. The variation of the percentage of imaginary frequencies with temperature during melting is akin to the variation of other properties. It is shown that confined clusters might exhibit inverse surface melting, unlike medium-to-large-sized free clusters that exhibit surface melting. Configurational-bias Monte Carte (CBMC) simulations of n-alkanes in zeolites Y and A are reported. CBMC method gives reliable estimates of the properties relating to the conformation of molecules. Changes in the conformational properties of n-butane and other longer n-alkanes such as n-hexane and n-heptane when they are confined in different zeolites are presented. The changes in the conformational properties of n-butane and n-hexane with temperature and concentration is discussed. In general, in zeolite Y as well as A, there is significant enhancement of the gauche population as compared to the pure unconfined fluid.

Item Type:	Journal Article
Publication:	Bulletin of Materials Science
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright of this article belongs to Indian Academy of Sciences.
Keywords:	Argon clusters;malkanes;zeolites;Monte Carlo;molecular dynamics.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Interdisciplinary Sciences > Supercomputer Education & Research Centre
Date Deposited:	04 Aug 2011 08:50
Last Modified:	04 Aug 2011 08:50
URI:	http://eprints.iisc.ac.in/id/eprint/38311

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