#
# 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) 2015--2018, Regents of the University of Minnesota.
# All rights reserved.
#
# Contributors:
#    Ryan S. Elliott
#    Andrew Akerson
#


This directory contains a Lennard-Jones model defined for the entire set of KIM
API particle types.

* Sigma parameters are set to (2^{-1/6})*r_0, where r_0 is the atomic covalent
  radius.  Covalent radii for elements 1--96 were taken from Wolfram
  Mathematica's `ElementData["CovalentRadius"]' command.  Covalent radii for
  elements 97--118 were taken from Fig. 3 of the article Pyykko, M. Atsumi,
  J. Chem. Eur. J. 15 (2009) 12770.

* Epsilon parameters are set to the bond dissociation energy.  Bond
  dissociation energies for elements 1--55, 57--60, and 61--84 were taken from
  the CRC Handbook of Chemistry and Physics, 91st Edition, Ed. W.H. Haynes,
  2010. (as posted here:
  http://staff.ustc.edu.cn/~luo971/2010-91-CRC-BDEs-Tables.pdf)

  The value (cohesive energy, in this case) for element 56 was obtained from
  p. 50 in Charles Kittel. Introduction to Solid State Physics, 8th
  edition. Hoboken, NJ: John Wiley & Sons, Inc, 2005.

  The bond dissociation energy value for element 61 was obtained from
  "Interpolation scheme for the cohesive energies for the lanthanides and
  actinides" Borje Johansson and Anders Rosengren, Phys. Rev. B 11, 1367 (1975).

  The bond dissociation energies for elements 85--118 were not found in the
  literature.  Thus, the values used here are approximated by subtracting 10%
  from the value for the element in the same Group (column) and previous Period
  (row) of the periodic table.

* Cutoff parameters are set to 4.0*sigma.  This corresponds to a cutoff energy
  of approximately epsilon/1024.

* Lorentz-Berthelot mixing rules are used for interactions between unlike
  particles. Each interaction potential is shifted to zero energy at its cutoff
  distance.