Rajappa, Chitra and Yashonath, Subramanian (1999) Levitation effect and its relationship with the underlying potential energy landscape. In: Journal of Chemical Physics, The, 110 (12). pp. 5960-5968.
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Positions of potential energy minima for spherical monatomic sorbates in zeolite NaY have been identified for different sizes of the sorbate. It is found that for small sorbates (sigma less than or equal to 4.96 Angstrom) there are only six adsorption sites per alpha-cage, which are located close to the inner surface of the alpha-cage. For larger sorbates, additional sites of comparable energies appear close to the 12-ring window which forms the bottleneck for intercage diffusion. Minimum energy paths between these sites have been computed. These suggest that the barriers for both intracage and intercage site-to-site migrations are comparable and decrease with increase in sorbate size. Earlier simulation studies on the diffusion of monatomic sorbates in zeolites indicated that there is a dramatic change in the nature of dependence of D on sorbate size around 4.96 Angstrom, for zeolite NaY. Therefore, the present results suggest that the dependence of D on sorbate size and the changes in the potential energy landscape are correlated. The sorbate-zeolite system is characterized by a flatter potential energy landscape when the sorbate size is large. (C) 1999 American Institute of Physics. [S0021-9606(99)51110-0].
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to American Institute of Physics.|
|Department/Centre:||Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Division of Information Sciences > Supercomputer Education & Research Centre
|Date Deposited:||23 Jun 2011 08:20|
|Last Modified:||23 Jun 2011 08:20|
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