The diffusion of halomethanes in zeolites is attracting a great deal of attention at present due to its relevance to environmental issues concerning ozone-depleting chlorofluorocarbons (CFCs) and the removal of chlorinated solvent residues from contaminated groundwater and soils. For example, NaY zeolite can be used to separate various hydrofluorocarbons (HFCs) during the manufacture of CFC substitudes. This thesis deals whit the diffusion of CFCl 3 , CF 2 Cl 2 , CF 3 Cl and CF 4 in FAU zeolite by means of molecular dynamics simulation. Molecular dynamics is a method for the simulation of thermodynamic behavior of materials in three phases –solid, liquid and gas- via forces, velocities and positions of particles. Among these factors, force is the most important factor. In Using these interatomic potentials, the diffusion coefficients, activation energy corresponding to the adsorbate motions within FAU zeolite, heats of adsorption and radial distribution functions (RDFs) for halomethanes in a wide range of temperature (200-700K) were evaluated. The interatomic potentials previously described for modeling the whole system were implemented in the DL_POLY program in the NVT ensemble and then NVE ensemble. A cutoff of 13 ? was used. A time step of 1fs was selected, with simulation run at loading of 8 molecules per unit cell. The simulations spanned a range of temperatures between 200 and 700K, each for teps (NVE ensemble), following teps of equilibration(NVT ensemble). We observed that the slope of the curves of MSD increase with temperature. The values of the diffusion coefficients increase with temperature. Diffusion coefficient depends on mass and dipole moment of halomethane molecules. Diffusion coefficients decrease with increase of mass and dipole moment. The predicted activation energies via Arrhenius equation were obtained. Activation energy increases with increase of mass and dipole moment. The simulated adsorption heats were estimated at the coverage of 1 molecule per unit cell, which decrease with temperature. Radial distribution functions of different atomic sites were obtained at various temperatures. Highest peak shifts were observed by increase of temperature
