<li>hbnewflag = use old or new hbond function style (0 or 1) (optional)</li>
<li>tripflag = apply stabilization to all triple bonds (0 or 1) (optional)</li>
<li>precision = precision for charge equilibration (optional)</li>
</ul>
</div>
<divclass="section"id="examples">
<h2>Examples</h2>
<preclass="literal-block">
pair_style reax
pair_style reax 10.0 0 1 1.0e-5
pair_coeff * * ffield.reax 3 1 2 2
pair_coeff * * ffield.reax 3 NULL NULL 3
</pre>
</div>
<divclass="section"id="description">
<h2>Description</h2>
<p>Style <em>reax</em> computes the ReaxFF potential of van Duin, Goddard and
co-workers. ReaxFF uses distance-dependent bond-order functions to
represent the contributions of chemical bonding to the potential
energy. There is more than one version of ReaxFF. The version
implemented in LAMMPS uses the functional forms documented in the
supplemental information of the following paper:
<aclass="reference internal"href="pair_reax_c.html#chenoweth-2008"><spanclass="std std-ref">(Chenoweth)</span></a>. The version integrated into LAMMPS matches
the most up-to-date version of ReaxFF as of summer 2010.</p>
<p>WARNING: pair style reax is now deprecated and will soon be retired. Users
should switch to <aclass="reference internal"href="pair_reax_c.html"><spanclass="doc">pair_style reax/c</span></a>. The <em>reax</em> style
differs from the <em>reax/c</em> style in the lo-level implementation details.
The <em>reax</em> style is a
Fortran library, linked to LAMMPS. The <em>reax/c</em> style was initially
implemented as stand-alone C code and is now integrated into LAMMPS as
a package.</p>
<p>LAMMPS requires that a file called ffield.reax be provided, containing
the ReaxFF parameters for each atom type, bond type, etc. The format
is identical to the ffield file used by van Duin and co-workers. The
filename is required as an argument in the pair_coeff command. Any
value other than “ffield.reax” will be rejected (see below).</p>
<p>LAMMPS provides several different versions of ffield.reax in its
potentials dir, each called potentials/ffield.reax.label. These are
documented in potentials/README.reax. The default ffield.reax
contains parameterizations for the following elements: C, H, O, N.</p>
<divclass="admonition note">
<pclass="first admonition-title">Note</p>
<pclass="last">We do not distribute a wide variety of ReaxFF force field files
with LAMMPS. Adri van Duin’s group at PSU is the central repository
for this kind of data as they are continuously deriving and updating
parameterizations for different classes of materials. You can submit
a contact request at the Materials Computation Center (MCC) website
<p>This pair style tallies a breakdown of the total ReaxFF potential
energy into sub-categories, which can be accessed via the <aclass="reference internal"href="compute_pair.html"><spanclass="doc">compute pair</span></a> command as a vector of values of length 14.
The 14 values correspond to the following sub-categories (the variable
names in italics match those used in the ReaxFF FORTRAN library):</p>
<olclass="arabic simple">
<li><em>eb</em> = bond energy</li>
<li><em>ea</em> = atom energy</li>
<li><em>elp</em> = lone-pair energy</li>
<li><em>emol</em> = molecule energy (always 0.0)</li>
<p>This pair style does not support the <aclass="reference internal"href="pair_modify.html"><spanclass="doc">pair_modify</span></a>
mix, shift, table, and tail options.</p>
<p>This pair style does not write its information to <aclass="reference internal"href="restart.html"><spanclass="doc">binary restart files</span></a>, since it is stored in potential files. Thus, you
need to re-specify the pair_style and pair_coeff commands in an input
script that reads a restart file.</p>
<p>This pair style can only be used via the <em>pair</em> keyword of the
<aclass="reference internal"href="run_style.html"><spanclass="doc">run_style respa</span></a> command. It does not support the
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