forked from lijiext/lammps
63 lines
1.5 KiB
HTML
63 lines
1.5 KiB
HTML
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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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</CENTER>
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<HR>
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<H3>improper_style fourier command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>improper_style fourier
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</PRE>
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<P><B>Examples:</B>
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</P>
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<PRE>improper_style fourier
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improper_coeff 1 100.0 180.0
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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>fourier</I> improper style uses the following potential:
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</P>
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<CENTER><IMG SRC = "Eqs/improper_fourier.jpg">
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</CENTER>
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<P>where K is the force constant and omega is the angle between the IL
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axis and the IJK plane:
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</P>
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<CENTER><IMG SRC = "Eqs/umbrella.jpg">
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</CENTER>
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<P>If all parameter (see bellow) is not zero, the all the three possible angles will taken in account.
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</P>
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<P>The following coefficients must be defined for each improper type via
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the <A HREF = "improper_coeff.html">improper_coeff</A> command as in the example
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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:
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</P>
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<UL><LI>K (energy)
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<LI>C0 (real)
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<LI>C1 (real)
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<LI>C2 (real)
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<LI>all (integer >= 0)
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</UL>
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<HR>
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<P><B>Restrictions:</B>
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</P>
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<P>This angle style can only be used if LAMMPS was built with the
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USER_MISC package. See the <A HREF = "Section_start.html#start_3">Making LAMMPS</A>
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section for more info on packages.
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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 = "improper_coeff.html">improper_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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</HTML>
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