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dc.contributor.advisorWang, Yan
dc.contributor.authorHe, Lijuan
dc.date.accessioned2014-01-13T16:20:37Z
dc.date.available2014-01-13T16:20:37Z
dc.date.created2013-12
dc.date.issued2013-09-17
dc.date.submittedDecember 2013
dc.identifier.urihttp://hdl.handle.net/1853/50248
dc.description.abstractOne of the most important design issues for phase change materials is to engineer the phase transition process. The challenge of accurately predicting a phase transition is estimating the true value of transition rate, which is determined by the saddle point with the minimum energy barrier between stable states on the potential energy surface (PES). In this thesis, a new algorithm for searching the minimum energy path (MEP) is presented. The new algorithm is able to locate both the saddle point and local minima simultaneously. Therefore no prior knowledge of the precise positions for the reactant and product on the PES is needed. Unlike existing pathway search methods, the algorithm is able to search multiple transition paths on the PES simultaneously, which gives us a more comprehensive view of the energy landscape than searching individual ones. In this method, a Bézier curve is used to represent each transition path. During the searching process, the reactant and product states are located by minimizing the two end control points of the curve, while the shape of the transition pathway is refined by moving the intermediate control points of the curve in the conjugate directions. A curve subdivision scheme is developed so that multiple transitions paths can be located. The algorithm is demonstrated by examples of LEPS potential, LEPS plus harmonic oscillator potential, and PESs defined by Rastrigin function and Schwefel function.
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technology
dc.subjectSaddle point
dc.subjectMultiple transition pathway
dc.subjectMEP
dc.subjectBézier curve
dc.subjectCurve subdivision scheme
dc.subject.lcshNanotechnology
dc.subject.lcshNanostructures
dc.subject.lcshPhase transformations (Statistical physics)
dc.subject.lcshAlgorithms
dc.titleA global search algorithm for phase transition pathways in computer-aided nano-design
dc.typeThesis
dc.description.degreeM.S.
dc.contributor.departmentMechanical Engineering
thesis.degree.levelMasters
dc.contributor.committeeMemberZhu, Ting
dc.contributor.committeeMemberJang, Seung Soon
dc.date.updated2014-01-13T16:20:37Z


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