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# CDDL HEADER START
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# The contents of this file are subject to the terms of the Common Development
# and Distribution License Version 1.0 (the "License").
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# include the License file in a prominent location with the name LICENSE.CDDL.
# If applicable, add the following below this CDDL HEADER, with the fields
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# Copyright (c) 2012, Regents of the University of Minnesota. All rights reserved.
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# Contributors:
# Ryan S. Elliott
# Ellad B. Tadmor
# Valeriu Smirichinski
# Amit Singh
#
#
# Release: This file is part of the openkim-api-vX.X.X package.
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This directory (Three_Body_Stillinger_Weber__MD_335816936951_001) contains Stillinger-Weber potential
Model driver written in C.
/*******************************************************************************
* For three-body potential any potential energy function for N-particle system can be written in the
* following form of two-body and three-body terms:
F(1, 2, ...., N) = sum_{i; 1 <= i < j <= N} phi_two(r; r = r_ij)
+ sum_{i; 1 <= i \neq j < k <= N} phi_three(r_ij, r_ik, r_jk);
* For Stillinger-Weber, two-body term phi_two is
phi_two(r) = epsilon * f_2(r_cap; r_cap = r/sigma); where f_2 is
f_2(r_cap) = A * ( B*r_cap^(-p) - r_cap^-q ) * exp(1/(r_cap - a)); when r_cap < a
= 0 when r_cap >= a
* and three-body term phi_three is
phi_three(r_ij, r_ik, r_jk) = epsilon * f_3(r1_cap, r2_cap, r3_cap); where
r1_cap = r_ij/sigma, r2_cap = r_ik/sigma, r3_cap = r_jk/sigma, and
f_3(r1_cap, r2_cap, r3_cap) = lambda * (exp(gamma((1/(r1_cap - a)) + (1/(r2_cap - a))))) * (costheta_jik - costheta_0)^2; when r1_cap < a && r2_cap < a
= 0; otherwise
costheta_jik = (r_ij^2 + r_ik^2 - r_jk^2) / (2*r_ij*r_ik).
*******************************************************************************/
For Silicon:
------------------------------------------------------------
| A = 7.049556277, B = 0.6022245584, p = 4, q = 0, |
| a = 1.80, lambda = 21.0, gamma = 1.2, |
| sigma = 2.0951, epsilon = 2.315 ev (for E_coh = 4.63 ev), |
| costheta_0 = -1/3 |
-------------------------------------------------------------
References:
1. F. H. Stillinger and T. A. Weber, "Computer simulation of local order in condensed phases of silicon", Phys. Rev. B, vol. 31, 5262-5271, 1985
2. Ellad B. Tadmor and Ronald E. Miller, Modeling Materials: Continuum, Atomistic and Multiscale Techniques, Cambridge University Press, 2011
It complies with the KIM API interface standard, using two neihgbor handling methods,
NEIGH_PURE_F and NEIGH_RVEC_F and iterator or locator mode. It publishes its parameters
and supports optional computation of `energy', 'forces', 'particleEnergy', 'process_dEdr',
and 'process_dE2dr2'. Its initializaton routine takes a KIM API object pointer and
a pointer to a string that contains all parameters which define a KIM Model
based on this KIM Model Driver.
To create a KIM Model from this Model Driver, a parameter file is required.
This file must have the follwing format:
Line 1: A
Line 2: B
Line 3: p
Line 4: q
Line 5: a
Line 6: lambda
Line 7: gamma
Line 8: sigma in Angstrom
Line 9: epsilon in ev
Line 10: costheta_0
Any additional lines will be silently ignored.
The following files are in this directory:
LICENSE.CDDL
The Common Development and Distribution License (CDDL) Version 1.0 file
Makefile
makefile to compile and build executables with GNU or Intel compilers
README
This file
Three_Body_Stillinger_Weber.c
C file that contains the implementation of the 3-body Stillinger-Weber potential
Model Driver
Three_Body_Stillinger_Weber.kim.tpl
Template KIM descriptor file containing all variables and methods that are
exposed by the driver through the KIM API interface. This file will be
used (by the make system) to generate a KIM descriptor file for each KIM
Model based on this Model Driver.