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Summary: Density Functional Theory Study of Silica Zeolite Structures: Stabilities and Mechanical
Properties of SOD, LTA, CHA, MOR, and MFI
R. Astala, Scott M. Auerbach,* and P. A. Monson
Department of Chemical Engineering, Department of Chemistry, UniVersity of Massachusetts Amherst,
Amherst, Massachusetts 01003
ReceiVed: February 11, 2004; In Final Form: April 9, 2004
We have investigated various silica zeolites using density functional theory with periodic supercells, plane
waves, and pseudopotentials. These zeolitic phases include silica sodalite, chabazite, mordenite, silica LTA,
and silicalite. Atom-level geometries, elastic properties, and cohesive energies are presented. Although the
zeolites exhibit a wide range of Si-O-Si angles and densities, the cohesive energies remain nearly constant.
The elastic properties vary significantly from one phase to another, and in some cases, large elastic anisotropies
are observed.
I. Introduction
Zeolites are nanoporous crystalline aluminosilicates frequently
used in important chemical industry applications.1 Their proper-
ties are determined by their nanoporous structures, which, in
turn, are determined by the details of crystal growth processes.
It is of great interest to understand the self-assembly and
crystallization of zeolites, with a focus on discovering new ways
to synthesize tailor-made pore structures. This issue is motivated
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