forked from lijiext/lammps
104 lines
3.7 KiB
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104 lines
3.7 KiB
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<HTML>
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<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>
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<H3>pair_style lcbop command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>pair_style lcbop
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</PRE>
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<P><B>Examples:</B>
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</P>
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<PRE>pair_style lcbop
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pair_coeff * * ../potentials/C.lcbop C
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>The <I>lcbop</I> pair style computes the long-range bond-order potential
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for carbon (LCBOP) of <A HREF = "#Los">(Los and Fasolino)</A>. See section II in
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that paper for the analytic equations associated with the potential.
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</P>
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<P>Only a single pair_coeff command is used with the <I>lcbop</I> style which
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specifies an LCBOP potential file with parameters for specific
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elements. These are mapped to LAMMPS atom types by specifying N
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additional arguments after the filename in the pair_coeff command,
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where N is the number of LAMMPS atom types:
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</P>
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<UL><LI>filename
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<LI>N element names = mapping of LCBOP elements to atom types
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</UL>
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<P>See the <A HREF = "pair_coeff.html">pair_coeff</A> doc page for alternate ways
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to specify the path for the potential file.
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</P>
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<P>As an example, if your LAMMPS simulation has 4 atom types and you want
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the 1st 3 to be C you would use the following pair_coeff command:
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</P>
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<PRE>pair_coeff * * C.lcbop C C C NULL
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</PRE>
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<P>The 1st 2 arguments must be * * so as to span all LAMMPS atom types.
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The first C argument maps LAMMPS atom type 1 to the C element in the
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LCBOP file. If a mapping value is specified as NULL, the mapping is
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not performed. This can be used when a <I>lcbop</I> potential is used as
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part of the <I>hybrid</I> pair style. The NULL values are placeholders for
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atom types that will be used with other potentials.
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</P>
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<P>The parameters/coefficients for the LCBOP potential as applied to C
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are listed in the C.lcbop file to agree with the original <A HREF = "#Los">(Los and
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Fasolino)</A> paper. Thus the parameters are specific to this
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potential and the way it was fit, so modifying the file should be done
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carefully.
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</P>
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<HR>
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<P><B>Mixing, shift, table, tail correction, restart, rRESPA info</B>:
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</P>
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<P>This pair style does not support the <A HREF = "pair_modify.html">pair_modify</A>
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mix, shift, table, and tail options.
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</P>
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<P>This pair style does not write its information to <A HREF = "restart.html">binary restart
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files</A>, since it is stored in potential files. Thus, you
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need to re-specify the pair_style and pair_coeff commands in an input
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script that reads a restart file.
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</P>
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<P>This pair style can only be used via the <I>pair</I> keyword of the
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<A HREF = "run_style.html">run_style respa</A> command. It does not support the
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<I>inner</I>, <I>middle</I>, <I>outer</I> keywords.
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</P>
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<P><B>Restrictions:</B>
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</P>
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<P>This pair styles is part of the MANYBODY package. It is only enabled
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if LAMMPS was built with that package (which it is by default). See
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the <A HREF = "Section_start.html#start_3">Making LAMMPS</A> section for more info.
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</P>
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<P>This pair potential requires the <A HREF = "newton.html">newton</A> setting to be
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"on" for pair interactions.
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</P>
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<P>The C.lcbop potential file provided with LAMMPS (see the potentials
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directory) is parameterized for metal <A HREF = "units.html">units</A>. You can use
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the LCBOP potential with any LAMMPS units, but you would need to
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create your own LCBOP potential file with coefficients listed in the
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appropriate units if your simulation doesn't use "metal" units.
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "pair_airebo.html">pair_airebo</A>, <A HREF = "pair_coeff.html">pair_coeff</A>
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</P>
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<P><B>Default:</B> none
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</P>
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<HR>
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<A NAME = "Los"></A>
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<P><B>(Los and Fasolino)</B> J. H. Los and A. Fasolino, Phys. Rev. B 68, 024107
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(2003).
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</P>
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</HTML>
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