Investigation of the dynamics of benzene in silicalite using transition-state theory ion-state
- Univ. of California, Berkeley, CA (United States) Lawrence Berkeley Lab., CA (United States)
The dynamics of benzene in silicalite at low loading was investigated using transition-state theory. Benzene was found to diffuse by infrequent hops between preferred adsorption sites. Potential energy minima and saddle points were located using an atomistic model, and diffusion paths connecting pairs of minima were constructed through each saddle point (transition state). The intrinsic reaction coordinate (IRC) approach was used to construct the diffusion paths in six dimensions. The IRC equations are presented for the motion of a rigid body (benzene) through a static potential field (silicalite). A rate constant for each transition between minima was calculated using a harmonic approximation to the potential energy function. From the rate constants, the self-diffusivity was computed with a dynamic Monte Carlo simulation. An activation energy of 36.7 kJ/mol was calculated. This is larger than the experimental value, and the predicted diffusivities are 1-2 orders of magnitude smaller than experiment. 51 refs., 7 figs., 3 tabs.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6602179
- Journal Information:
- Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:46; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360606 -- Other Materials-- Physical Properties-- (1992-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
ACTIVATION ENERGY
ADSORPTION
AROMATICS
BENZENE
CALCULATION METHODS
COMPILED DATA
DATA
DIFFUSION
ENERGY
HYDROCARBONS
INFORMATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
MINERALS
MONTE CARLO METHOD
NUMERICAL DATA
ORGANIC COMPOUNDS
SADDLE-POINT METHOD
SILICATE MINERALS
SORPTION
SPECTROSCOPY
ZEOLITES