Abstract
We introduce a massively parallel replica-exchange grand-canonical sampling algorithm to simulate materials at realistic conditions, in particular surfaces and clusters in reactive atmospheres. Its purpose is to determine in an automated fashion equilibrium phase diagrams for a given potential-energy surface and for any observable sampled in the grand-canonical ensemble. The approach enables an unbiased sampling of the phase space and is embarrassingly parallel. It is demonstrated for a model of the Lennard-Jones system describing a surface in contact with a gas phase. Furthermore, the algorithm is applied to clusters () in contact with an atmosphere, with all interactions described at the ab initio level, i.e., via density-functional theory, with the Perdew-Burke-Ernzerhof gradient-corrected exchange-correlation functional. We identify the most thermodynamically stable phases at finite ) conditions.
1 More- Received 27 August 2019
DOI:https://doi.org/10.1103/PhysRevB.100.174106
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