8MolecularDynamicsSimulation PolyatomicMoleculesinModel
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ALEKSANDERBRODKAInstituteofPhysics,UniversityofSilesia,Katowice, Poland I.Introduction II.MolecularDynamicsSimulationofMoleculesinModelPore A.A"closed"poremodel B.An"open"poremodel C.Dynamicsofmoleculesinpores 244 245 246 247 III.MoleculesinCylindricalSilicaPores251 A.Cyclohexaneatlowdensities251 B.C60/C6H12mixture257 C.Sulfurhexafluoride259 D.Acetone265 IV.Liquid-PlasticPhaseTransitionofCyclohexaneinSilicaCavities271 V.ConcludingRemarks References Computersimulationisausefulmethodtostudypropertiesofmoleculesnotonly inbulkphasesbutalsoinporousmaterials(forreviewseeRef.l).Behaviorof moleculestrappedinaporedependsontheporeshape,featuresofthesolidsurface,andnatureofsurfaceinteractions.Thesefactorscanberelativelyeasilymodifiedinthesimulationofmoleculardynamics(MD),whichgivespossibilitiesto investigatestructuralandtime-dependentpropertiesofmolecules.However,dueto thecomplexityofthesystem(porousmaterialwithadsorbedmolecules)itisnecessarytomakecertainassumptionsabouttheshapeoftheporeanditssurface,as well as to model the molecules. In many computer simulations, pores are represented by slits between two parallel walls of structureless surfaces [2-7] or crystalline ones [8-9], whereas in others the pores are in the shape of a cylinder with smooth surfaces [10-12]. In all these studies, molecules are approximated by onecenter particles, and the MD calculations are limited to simulations of the translational motion.