# # CDDL HEADER START # # The contents of this file are subject to the terms of the Common Development # and Distribution License Version 1.0 (the "License"). # # You can obtain a copy of the license at # http://www.opensource.org/licenses/CDDL-1.0. See the License for the # specific language governing permissions and limitations under the License. # # When distributing Covered Code, include this CDDL HEADER in each file and # 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 # enclosed by brackets "[]" replaced with your own identifying information: # # Portions Copyright (c) [yyyy] [name of copyright owner]. All rights reserved. # # CDDL HEADER END # # # Copyright (c) 2013--2015, Regents of the University of Minnesota. # All rights reserved. # # Contributors: # Ryan S. Elliott # Ellad B. Tadmor # Valeriu Smirichinski # Hao Xu This directory contains a Morse pair potential Model driver written in C. phi(r) = epsilon * ( - exp[ -2*C*(r - Rzero) ] + 2*exp[ -C*(r - Rzero) ] ) * S(r, logisticWidth, logisticR0) where S(r, logisticWidth, logisticR0) is the logistic function. S(r, logisticWidth, logisticR0) = 1/(1 + exp( -logisticWidth*[r - logisticR0])) The choice of logisticR0 = cutoff + 7/logisticWidth is designed so that S(cutoff) ~ 0.001. This model driver publishes its parameters, and supports optional computation of `energy', `forces', `particleEnergy', `process_dEdr', and `process_dE2dr2'. To create a KIM Model from this Model Driver, a parameter file is required. This file must have the following format: Line 1: Species name Line 2: `cutoff' value in Angstroms Line 3: `logisticWidth' value as pure number > 0.0 Line 4: Morse `epsilon' value in eV Line 5: Morse `C' value in 1/Angstroms Line 6: Morse `Rzero' value in Angstroms Any additional lines will be silently ignored.