Adaptive Treatment of van der Waals Interactions in Empirical Bon
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Adaptive Treatment of van der Waals Interactions in Empirical Bon
Clemson UniversityTigerPrintsAll DissertationsDissertations39203Adaptive Treatment of van der Waals Interactions in Empirical Bond-Order Potentials wi Adaptive Treatment of van der Waals Interactions in Empirical Bonith Application to Junction Formation in Carbon NanotubesAibing LiuCleniiũn Univenity, aliu(.?clenison.eduFollow this and additional works at: https: / /tigerprints.cletnson.edu/all_dissertai ỈO1IS& Part of the Physical Chemistry CommonsRecommended CitationLiu. Albing, 'Adaptive Treatment of van der Adaptive Treatment of van der Waals Interactions in Empirical Bon Waal* Interactions in Empirical Bond-Order Potentials with Application to Junction Formation in Carbon Nanotubes" (2lW). AW Dwscrtdrwnj. so.https: //Adaptive Treatment of van der Waals Interactions in Empirical Bon
tigerpnntsclemsoiiedu/aU_dissertations/ so'I his. 9ixM.fUtio.-i rt brought to you for free and open access by the DMcertatlon* at TlgcrPnnti. It hl* bClemson UniversityTigerPrintsAll DissertationsDissertations39203Adaptive Treatment of van der Waals Interactions in Empirical Bond-Order Potentials wi Adaptive Treatment of van der Waals Interactions in Empirical BonTIVE TREATMENT OF VAN DER XyAALS INTER ACTIONS IN EMPIRICAL BOND-ORDER POTENTIALS WITH APPLICATION TO JUNCTION FORMATION IN CARBON NANOTUBESA DissertationPresented to the Graduate School of Clemson UniversityIn Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Chemistry.by Adaptive Treatment of van der Waals Interactions in Empirical Bon.Aibing Lin May 2007Accepter! by:Dr. Steven J. Stuart. Committee ChairDr. Arkady KholodenkoDr. Robert LatourDr. Brian DominyABSTRACTMolecular dynamicsAdaptive Treatment of van der Waals Interactions in Empirical Bon
(MD) simulation of reactive condensed-phase hydrocarbon systems is a chỉdlenging research area. The AIREBO potential is particularly useful ill tins Clemson UniversityTigerPrintsAll DissertationsDissertations39203Adaptive Treatment of van der Waals Interactions in Empirical Bond-Order Potentials wi Adaptive Treatment of van der Waals Interactions in Empirical Bonficant intermolecular interactions.The first part of this dissertation describes a method to adaptively incorporate van dor Waals interaction of carbon atoms into the AIREBO force field. In bond-order potentials, the covalent bonding interactions adapt to the local chemical environment, allowing bon Adaptive Treatment of van der Waals Interactions in Empirical Bonded interactions to change in response to local chemical changes. Nonbonded interactions should adjust to their chemical environment as well, althoughAdaptive Treatment of van der Waals Interactions in Empirical Bon
this adaptivity has been somewhat limited in previous implementations. Here the AIREBO potential is extended to include an adaptive Lennard-Jones potClemson UniversityTigerPrintsAll DissertationsDissertations39203Adaptive Treatment of van der Waals Interactions in Empirical Bond-Order Potentials wi Adaptive Treatment of van der Waals Interactions in Empirical Bon* ami its gradient remain continuous, allowing it to be used for dynamics simulations. This new potential is parameterized for hydrocarbons, and is fit to the energetics and densities of a variety of condensed phase molecular hydrocarbons. The resulting model is more accurate for modeling aromatic a Adaptive Treatment of van der Waals Interactions in Empirical Bonmi other unsaturated hydrocarbon species, for which the original ALREBO potential had some deficiencies. Testing on compounds not used in the fittingAdaptive Treatment of van der Waals Interactions in Empirical Bon
procedure shows that the new model performs substantially better in predict iug heats of vaporization ami pressures (or densities) of condensed-phase Clemson UniversityTigerPrintsAll DissertationsDissertations39203Adaptive Treatment of van der Waals Interactions in Empirical Bond-Order Potentials wi Adaptive Treatment of van der Waals Interactions in Empirical Bonhas found many applications in recent years. Junctions between heterostructured iicUiotubes arc! of particular interest because of their possible application in nanoscale devices. Simulation is performed on the formation of junctions by Ar ion irradiation of nanotubes using the AIREBO force field. T Adaptive Treatment of van der Waals Interactions in Empirical Bonwo groups of nanotubes are used in Illis research. One includes larger nanotubes of diameter 13 A. another includes smaller nanotubes of diameter abouAdaptive Treatment of van der Waals Interactions in Empirical Bon
t 7-8 A. Nanotube junction formation under different bombardment ion energies is explored. Ill both large and small nanotubes, junctions can be formedClemson UniversityTigerPrintsAll DissertationsDissertations39203Adaptive Treatment of van der Waals Interactions in Empirical Bond-Order Potentials wi Adaptive Treatment of van der Waals Interactions in Empirical Bonged by high energy ious. The different types of defects created by ion impact are also investigated. Cross-links in the nanotube intersection are used as a primary index of junction formation. A comparison of longer relaxation and cooling limes is also performed. The evaluation of conductivity of na Adaptive Treatment of van der Waals Interactions in Empirical Bonnotube junctions during simulation is explored. For (10.(1) nanotubes, conductance across the junction becomes non-zero after the first impact for 330Adaptive Treatment of van der Waals Interactions in Empirical Bon
eV energy impact.DEDICATIONI dedicate this thesis to my loving wife. Without her support and understanding, this work would not have been completed.Clemson UniversityTigerPrintsAll DissertationsDissertations39203Adaptive Treatment of van der Waals Interactions in Empirical Bond-Order Potentials wiClemson UniversityTigerPrintsAll DissertationsDissertations39203Adaptive Treatment of van der Waals Interactions in Empirical Bond-Order Potentials wiGọi ngay
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