forked from lijiext/lammps
87 lines
2.8 KiB
HTML
87 lines
2.8 KiB
HTML
<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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<HR>
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<H3>pair_style lj/smooth/linear 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 lj/smooth/linear Rc
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</PRE>
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<UL><LI>Rc = cutoff for lj/smooth/linear interactions (distance units)
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>pair_style lj/smooth/linear 5.456108274435118
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pair_coeff * * 0.7242785984051078 2.598146797350056
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pair_coeff 1 1 20.0 1.3 9.0
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Style <I>lj/smooth/linear</I> computes a LJ interaction that combines the
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standard 12/6 Lennard-Jones function and subtracts a linear term that
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includes the cutoff distance Rc, as in this formula:
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</P>
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<CENTER><IMG SRC = "Eqs/pair_lj_cut_smooth.jpg">
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</CENTER>
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<P>At the cutoff Rc, the energy and force (its 1st derivative) will be 0.0.
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</P>
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<P>The following coefficients must be defined for each pair of atoms
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types via the <A HREF = "pair_coeff.html">pair_coeff</A> command as in the examples
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above, or in the data file or restart files read by the
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<A HREF = "read_data.html">read_data</A> or <A HREF = "read_restart.html">read_restart</A>
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commands, or by mixing as described below:
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</P>
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<UL><LI>epsilon (energy units)
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<LI>sigma (distance units)
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<LI>cutoff (distance units)
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</UL>
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<P>The last coefficient is optional. If not specified, the global value
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for Rc is used.
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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>For atom type pairs I,J and I != J, the epsilon and sigma coefficients
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and cutoff distance can be mixed. The default mix value is geometric.
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See the "pair_modify" command for details.
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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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shift option for the energy of the pair interaction.
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</P>
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<P>The <A HREF = "pair_modify.html">pair_modify</A> table option is not relevant for
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this pair style.
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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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tail option for adding long-range tail corrections to energy and
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pressure, since the energy of the pair interaction is smoothed to 0.0
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at the cutoff.
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</P>
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<P>This pair style writes its information to <A HREF = "restart.html">binary restart
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files</A>, so pair_style and pair_coeff commands do not need
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to be specified in an input 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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<HR>
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<P><B>Restrictions:</B> none
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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_coeff.html">pair_coeff</A>, <A HREF = "pair_lj_smooth.html">pair lj/smooth</A>
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</P>
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<P><B>Default:</B> none
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</P>
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</HTML>
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