<p>where Ri and Rj are the radii of the two particles and Rc is the
cutoff.</p>
<p>In contrast to <aclass="reference internal"href="pair_yukawa.html"><spanclass="doc">pair_style yukawa</span></a>, this functional
form arises from the Coulombic interaction between two colloid
particles, screened due to the presence of an electrolyte, see the
book by <aclass="reference internal"href="#safran"><spanclass="std std-ref">Safran</span></a> for a derivation in the context of DVLO
theory. <aclass="reference internal"href="pair_yukawa.html"><spanclass="doc">Pair_style yukawa</span></a> is a screened Coulombic
potential between two point-charges and uses no such approximation.</p>
<p>This potential applies to nearby particle pairs for which the Derjagin
approximation holds, meaning h << Ri + Rj, where h is the
surface-to-surface separation of the two particles.</p>
<p>When used in combination with <aclass="reference internal"href="pair_colloid.html"><spanclass="doc">pair_style colloid</span></a>,
the two terms become the so-called DLVO potential, which combines
electrostatic repulsion and van der Waals attraction.</p>
<p>The following coefficients must be defined for each pair of atoms
types via the <aclass="reference internal"href="pair_coeff.html"><spanclass="doc">pair_coeff</span></a> command as in the examples
above, or in the data file or restart files read by the
<aclass="reference internal"href="read_data.html"><spanclass="doc">read_data</span></a> or <aclass="reference internal"href="read_restart.html"><spanclass="doc">read_restart</span></a>
commands, or by mixing as described below:</p>
<ulclass="simple">
<li>A (energy/distance units)</li>
<li>cutoff (distance units)</li>
</ul>
<p>The prefactor A is determined from the relationship between surface
charge and surface potential due to the presence of electrolyte. Note
that the A for this potential style has different units than the A
used in <aclass="reference internal"href="pair_yukawa.html"><spanclass="doc">pair_style yukawa</span></a>. For low surface
potentials, i.e. less than about 25 mV, A can be written as:</p>
<p>The last coefficient is optional. If not specified, the global
yukawa/colloid cutoff is used.</p>
<hrclass="docutils"/>
<p>Styles with a <em>gpu</em>, <em>intel</em>, <em>kk</em>, <em>omp</em>, or <em>opt</em> suffix are
functionally the same as the corresponding style without the suffix.
They have been optimized to run faster, depending on your available
hardware, as discussed in <aclass="reference internal"href="Section_accelerate.html"><spanclass="doc">Section 5</span></a>
of the manual. The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
issues.</p>
<p>These accelerated styles are part of the GPU, USER-INTEL, KOKKOS,
USER-OMP and OPT packages, respectively. They are only enabled if
LAMMPS was built with those packages. See the <aclass="reference internal"href="Section_start.html#start-3"><spanclass="std std-ref">Making LAMMPS</span></a> section for more info.</p>
<p>You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the <aclass="reference internal"href="Section_start.html#start-7"><spanclass="std std-ref">-suffix command-line switch</span></a> when you invoke LAMMPS, or you can
use the <aclass="reference internal"href="suffix.html"><spanclass="doc">suffix</span></a> command in your input script.</p>
<p>See <aclass="reference internal"href="Section_accelerate.html"><spanclass="doc">Section 5</span></a> of the manual for
more instructions on how to use the accelerated styles effectively.</p>
<p>For atom type pairs I,J and I != J, the A coefficient and cutoff
distance for this pair style can be mixed. A is an energy value mixed
like a LJ epsilon. The default mix value is <em>geometric</em>. See the
“pair_modify” command for details.</p>
<p>This pair style supports the <aclass="reference internal"href="pair_modify.html"><spanclass="doc">pair_modify</span></a> shift
option for the energy of the pair interaction.</p>
<p>The <aclass="reference internal"href="pair_modify.html"><spanclass="doc">pair_modify</span></a> table option is not relevant
for this pair style.</p>
<p>This pair style does not support the <aclass="reference internal"href="pair_modify.html"><spanclass="doc">pair_modify</span></a>
tail option for adding long-range tail corrections to energy and
pressure.</p>
<p>This pair style writes its information to <aclass="reference internal"href="restart.html"><spanclass="doc">binary restart files</span></a>, so pair_style and pair_coeff commands do not need
to be specified 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
<p>This style is part of the COLLOID package. It is only enabled if
LAMMPS was built with that package. See the <aclass="reference internal"href="Section_start.html#start-3"><spanclass="std std-ref">Making LAMMPS</span></a> section for more info.</p>
<p>This pair style requires that atoms be finite-size spheres with a
diameter, as defined by the <aclass="reference internal"href="atom_style.html"><spanclass="doc">atom_style sphere</span></a>
command.</p>
<p>Per-particle polydispersity is not yet supported by this pair style;
per-type polydispersity is allowed. This means all particles of the
same type must have the same diameter. Each type can have a different
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