2013-09-17 07:02:40 +08:00
|
|
|
<HTML>
|
|
|
|
|
<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
|
|
|
|
|
</CENTER>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<HR>
|
|
|
|
|
|
|
|
|
|
<H3>pair_style zbl command
|
|
|
|
|
</H3>
|
2013-10-30 23:41:56 +08:00
|
|
|
<H3>pair_style zbl/omp command
|
|
|
|
|
</H3>
|
2013-09-17 07:02:40 +08:00
|
|
|
<P><B>Syntax:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<PRE>pair_style zbl inner outer
|
|
|
|
|
</PRE>
|
|
|
|
|
<UL><LI>inner = distance where switching function begins
|
|
|
|
|
<LI>outer = global cutoff for ZBL interaction
|
|
|
|
|
</UL>
|
|
|
|
|
<P><B>Examples:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<PRE>pair_style zbl 3.0 4.0
|
|
|
|
|
pair_coeff * * 73.0
|
|
|
|
|
pair_coeff 1 1 14.0
|
|
|
|
|
</PRE>
|
|
|
|
|
<P><B>Description:</B>
|
|
|
|
|
</P>
|
2013-09-18 03:08:43 +08:00
|
|
|
<P>Style <I>zbl</I> computes the Ziegler-Biersack-Littmark (ZBL) screened nuclear
|
|
|
|
|
repulsion for describing high-energy collisions between atoms.
|
|
|
|
|
<A HREF = "#Ziegler">(Ziegler)</A>. It includes an additional switching function
|
|
|
|
|
that ramps the energy, force, and curvature smoothly to zero
|
|
|
|
|
between an inner and outer cutoff. The potential
|
|
|
|
|
energy due to a pair of atoms at a distance r_ij is given by:
|
|
|
|
|
</P>
|
|
|
|
|
<CENTER><IMG SRC = "Eqs/pair_zbl.jpg">
|
|
|
|
|
</CENTER>
|
2014-03-18 22:59:36 +08:00
|
|
|
<P>where e is the electron charge, epsilon_0 is the electrical
|
|
|
|
|
permittivity of vacuum, and Z_i and Z_j are the nuclear charges of the
|
|
|
|
|
two atoms. The switching function S(r) is identical to that used by
|
|
|
|
|
<A HREF = "pair_gromacs.html">pair_style lj/gromacs</A>. Here, the inner and outer
|
|
|
|
|
cutoff are the same for all pairs of atom types.
|
2013-09-18 03:08:43 +08:00
|
|
|
</P>
|
|
|
|
|
<P>The following coefficient must be defined for each pair of atom types
|
2013-09-17 23:10:01 +08:00
|
|
|
via the <A HREF = "pair_coeff.html">pair_coeff</A> command as in the examples above,
|
2014-03-18 22:59:36 +08:00
|
|
|
or in the LAMMPS data file. Z can not be specified for two different
|
|
|
|
|
atoms types. Therefore the lists of atom types I and atom types J
|
|
|
|
|
must match.
|
2013-09-17 23:10:01 +08:00
|
|
|
</P>
|
2014-03-18 22:59:36 +08:00
|
|
|
<UL><LI>Z (multiples of proton charge, e.g. 13.0 for aluminum)
|
2013-09-17 23:10:01 +08:00
|
|
|
</UL>
|
|
|
|
|
<P>Although Z must be defined for all atom type pairs I,J, it is only
|
2013-09-18 03:08:43 +08:00
|
|
|
stored for individual atom types, i.e. when I = J. Z is normally equal
|
|
|
|
|
to the atomic number of the atom type.
|
|
|
|
|
</P>
|
|
|
|
|
<P>IMPORTANT NOTE: The numerical values of the exponential decay
|
2013-09-18 03:50:20 +08:00
|
|
|
constants in the screening function depend on the unit of distance. In
|
|
|
|
|
the above equation they are given for units of angstroms. LAMMPS will
|
|
|
|
|
automatically convert these values to the distance unit of the
|
|
|
|
|
specified LAMMPS <A HREF = "units.html">units</A> setting. The values of Z should
|
2014-03-18 22:59:36 +08:00
|
|
|
always be given as multiples of a proton's charge, e.g. 29.0 for
|
|
|
|
|
copper.
|
2013-09-17 07:02:40 +08:00
|
|
|
</P>
|
|
|
|
|
<HR>
|
|
|
|
|
|
2014-08-15 00:30:25 +08:00
|
|
|
<P>Styles with a <I>cuda</I>, <I>gpu</I>, <I>intel</I>, <I>kk</I>, <I>omp</I>, or <I>opt</I> 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 <A HREF = "Section_accelerate.html">Section_accelerate</A>
|
|
|
|
|
of the manual. The accelerated styles take the same arguments and
|
|
|
|
|
should produce the same results, except for round-off and precision
|
|
|
|
|
issues.
|
2013-10-30 23:41:56 +08:00
|
|
|
</P>
|
2014-08-15 00:30:25 +08:00
|
|
|
<P>These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
|
|
|
|
|
KOKKOS, USER-OMP and OPT packages, respectively. They are only
|
|
|
|
|
enabled if LAMMPS was built with those packages. See the <A HREF = "Section_start.html#start_3">Making
|
|
|
|
|
LAMMPS</A> section for more info.
|
2013-10-30 23:41:56 +08:00
|
|
|
</P>
|
|
|
|
|
<P>You can specify the accelerated styles explicitly in your input script
|
|
|
|
|
by including their suffix, or you can use the <A HREF = "Section_start.html#start_7">-suffix command-line
|
|
|
|
|
switch</A> when you invoke LAMMPS, or you can
|
|
|
|
|
use the <A HREF = "suffix.html">suffix</A> command in your input script.
|
|
|
|
|
</P>
|
|
|
|
|
<P>See <A HREF = "Section_accelerate.html">Section_accelerate</A> of the manual for
|
|
|
|
|
more instructions on how to use the accelerated styles effectively.
|
|
|
|
|
</P>
|
|
|
|
|
<HR>
|
|
|
|
|
|
2013-09-17 07:02:40 +08:00
|
|
|
<P><B>Mixing, shift, table, tail correction, restart, rRESPA info</B>:
|
|
|
|
|
</P>
|
2013-09-18 03:50:20 +08:00
|
|
|
<P>Mixing is not relevant for this pair style, since as explained above,
|
|
|
|
|
Z values are stored on a per-type basis, and both Zi and Zj are used
|
|
|
|
|
explicitly in the ZBL formula.
|
2013-09-17 07:02:40 +08:00
|
|
|
</P>
|
2013-09-18 03:50:20 +08:00
|
|
|
<P>The ZBL pair style does not support the <A HREF = "pair_modify.html">pair_modify</A>
|
|
|
|
|
shift option, since the ZBL interaction is already smoothed to 0.0 at
|
|
|
|
|
the cutoff.
|
2013-09-17 07:02:40 +08:00
|
|
|
</P>
|
2013-09-18 03:50:20 +08:00
|
|
|
<P>The <A HREF = "pair_modify.html">pair_modify</A> table option is not relevant for
|
|
|
|
|
this pair style.
|
2013-09-17 07:02:40 +08:00
|
|
|
</P>
|
2013-09-18 03:50:20 +08:00
|
|
|
<P>This pair style does not support the <A HREF = "pair_modify.html">pair_modify</A>
|
|
|
|
|
tail option for adding long-range tail corrections to energy and
|
|
|
|
|
pressure, since there are no corrections for a potential that goes to
|
|
|
|
|
0.0 at the cutoff.
|
2013-09-17 07:02:40 +08:00
|
|
|
</P>
|
2013-09-18 03:50:20 +08:00
|
|
|
<P>This pair style does not write information to <A HREF = "restart.html">binary restart
|
|
|
|
|
files</A>, so pair_style and pair_coeff commands must be
|
|
|
|
|
specified in an input script that reads a restart file.
|
2013-09-17 07:02:40 +08:00
|
|
|
</P>
|
2013-09-18 03:50:20 +08:00
|
|
|
<P>This pair style can only be used via the <I>pair</I> keyword of the
|
|
|
|
|
<A HREF = "run_style.html">run_style respa</A> command. It does not support the
|
|
|
|
|
<I>inner</I>, <I>middle</I>, <I>outer</I> keywords.
|
2013-09-17 07:02:40 +08:00
|
|
|
</P>
|
|
|
|
|
<HR>
|
|
|
|
|
|
|
|
|
|
<P><B>Restrictions:</B> none
|
|
|
|
|
</P>
|
|
|
|
|
<P><B>Related commands:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<P><A HREF = "pair_coeff.html">pair_coeff</A>
|
|
|
|
|
</P>
|
|
|
|
|
<P><B>Default:</B> none
|
|
|
|
|
</P>
|
|
|
|
|
<HR>
|
|
|
|
|
|
2013-09-18 03:08:43 +08:00
|
|
|
<A NAME = "Ziegler"></A>
|
2013-09-17 07:02:40 +08:00
|
|
|
|
2013-09-18 03:08:43 +08:00
|
|
|
<P><B>(Ziegler)</B> J.F. Ziegler, J. P. Biersack and U. Littmark, "The
|
2013-09-17 23:10:01 +08:00
|
|
|
Stopping and Range of Ions in Matter," Volume 1, Pergamon, 1985.
|
2013-09-17 07:02:40 +08:00
|
|
|
</P>
|
|
|
|
|
</HTML>
|
