title: Predicting polymeric crystal structures by evolutionary algorithms.
abstract: The recently developed evolutionary algorithm USPEX proved to be a tool that enables accurate and reliable prediction of structures. Here we extend this method to predict the crystal structure of polymers by constrained evolutionary search, where each monomeric unit is treated as a building block with fixed connectivity. This greatly reduces the search space and allows the initial structure generation with different sequences and packings of these blocks. The new constrained evolutionary algorithm is successfully tested and validated on a diverse range of experimentally known polymers, namely, polyethylene, polyacetylene, poly(glycolic acid), poly(vinyl chloride), poly(oxymethylene), poly(phenylene oxide), and poly (p-phenylene sulfide). By fixing the orientation of polymeric chains, this method can be further extended to predict the structures of complex linear polymers, such as all polymorphs of poly(vinylidene fluoride), nylon-6 and cellulose. The excellent agreement between predicted crystal structures and experimentally known structures assures a major role of this approach in the efficient design of the future polymeric materials.
authors.affiliation: Department of Geosciences, Stony Brook University, Center for Materials by Design, Institute for Advanced Computational Science, Stony Brook, New York 11794, USA.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06626, USA.
authors.forename: Vinit
authors.initials: V
authors.lastname: Sharma
authors.affiliation: Department of Geosciences, Stony Brook University, Center for Materials by Design, Institute for Advanced Computational Science, Stony Brook, New York 11794, USA.
authors.forename: Artem R
authors.initials: AR
authors.lastname: Oganov
authors.affiliation: Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06626, USA.
authors.forename: Ramamurthy
authors.initials: R
authors.lastname: Ramprasad