HRMC_2.1: Hybrid Reverse Monte Carlo method with silicon, carbon, germanium and silicon carbide potentials

Abstract

The Hybrid Reverse Monte Carlo (HRMC) code models the atomic structure of materials via the use of a combination of constraints including experimental diffraction data and an empirical energy potential. In this version 2.1 update, an empirical potential for silicon-carbide has been added to the code along with an experimentally motivated constraint on the bond type fraction applicable to systems containing multiple elements. New version program summaryProgram title: HRMC version 2.1Catalogue identifier: AEAO_v2_1Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAO_v2_1.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 114084No. of bytes in distributed program, including test data, etc.: 1289369Distribution format: tar.gzProgramming language: FORTRAN 90.Computer: any computer capable of running executables produced by the Fortran 90 compiler. For example, the code runs in Windows 7, once compiled with the GNU Fortran 95 compiler.Operating system: Unix, Windows.Classification: 7.7.Catalogue identifier of previous version: AEAO_v2_0Journal reference of previous version: Comput. Phys. Comm. 184 (2013) 1946Does the new version supersede the previous version?: yesNature of problem:atomic modelling using a combination of empirical potentials, fits to experimental data and other chemically or physically motivated constraints.Solution method:single move Metropolis Monte Carlo method used to minimize the total energy and discrepancy between simulation and experimental data.Reasons for new version:extension of capabilities from old version.Summary of revisions:1.Inclusion of a bond-order potential for silicon carbide (P. Erhart, K. Albe, Phys. Rev. B 71 (2005) 035211). The selection of this potential is via the POT_TYPE parameter in the HRMC.inp file and the number of carbon and silicon atoms needs to be specified via the configA and configB parameters.2.Inclusion of a constraint on the bond type fraction for multi-elemental systems. If a simulation has elements A, B and C, this constraint allows one to fix for element A, the fraction of A–A, A–B and A–C bonds (which should sum to unity) and similarly for elements B and C. The constraint is turned on via the BT_OPTION in the HRMC.inp file and it has its constraint weightings labelled in each stage alongside the other constraint weightings. The BT_OPT(1), BT_OPT(2) and BT_OPT(3) parameters are used to select which elements have their bond type fractions fitted via this constraint.3.A new file is output called data_xyzdetail.dat. This file contains lists of the neighbour separations, bond angles and dihedral angles.4.The header file hrmc.h has been replaced with hrmc_data.f90 which replaces the common block with a module to define global variables.Running time:1000 s for test run on a Intel Xeon 2.93 GHz—Nehalem series processor