5099

4796

كارشناسي ارشد

شيمي فيزيك

اصفهان: دانشگاه صنعتي اصفهان،دانشكده شيمي

1388

دوازده،81ص.:مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

بيژن نجفي،سامان علوي

حسن حدادزاده

89/1/21

يوسف غائب،محمد ژياني

شيمي

ID4796

به فارسي و انگليسي:قابل رويت در نسخه ديجيتالي

82 Calculation and investigation of self diffusivity of nitrogen and carbon monoxide gases in ITQ 7 zeolite via molecular dynamics simulation Fatemeh Amirseifadini f amirseifadini@gmail come mail March 6 2010 Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 IranLanguage Farsi Degree M ScBijan Najafi najafi@cc iut ac irSaman Alavi samanalavi@gmail com Abstract In this thesis molecular dynamics simulation has been used to study of the diffusion of nitrogen andcarbon monoxide molecules in an almost new zeolite with ISV code and Si64O128 chemical formula Zeolitesare an important class of molecular sieves in which separations are obtained by selecting the pore size suchthat in mixtures molecules that are too large are being blocked The basic building blocks of zeolites arecorner sharing TO4 units where the T atoms usually refer to Si Al or in some cases also P Thesetetrahedrals can form different types of units such as 6 rings 8 rings or 12 rings From a scientific point ofview zeolites are challenging As most of the activity occurs inside the material it is very difficult to carryout experiments that provide us information at the molecular level ITQ 7 structure type ISV has a three dimensional system of large pores defined by windows containing 12 member rings of about 6 in diameterMolecular 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 mostimportant factor In classical molecular dynamics simulation force is obtained from the classical potential each atom in the zeolite is assumed to interact with each site on the adsorbed molecules through both aLennard Jones potential and electrostatic interactions All interatomic interactions between the atoms in thesimulation box and the nearest image sites were calculated within a cutoff distance of Rcutoff 13 for allsimulated systems Simulations were performed at loadings of 4 6 8 10 12 14 16 18 and 20 nitrogenmolecules per unit cell and at loadings of 4 8 12 and 20 carbon monoxide molecules per unit cell at 200 K 298 K 400 K 500 K 600 K and 700 K temperatures The main purpose of this simulation is the study of properties such as the mean square displacement diffusion coefficient radial distribution function adsorption energy and activation energy In all thesimulations via DL POLY2 software pressure and time step of each system were fixed at 1 bar and 0 001 psrespectively First the simulations for each loading were performed in canonical ensemble at six differenttemperatures during 100 ps 100 000 steps to reach the equilibration of the systems Then each of theequilibrium systems was simulated in micro canonical ensemble during 100 ps 100 000 steps to get the

بيژن نجفي،سامان علوي

حسن حدادزاده

يوسف غائب،محمد ژياني