2006-09-22 00:22:34 +08:00
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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>improper_style harmonic 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 harmonic
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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 harmonic
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improper_coeff 1 100.0 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>harmonic</I> improper style uses the potential
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</P>
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<CENTER><IMG SRC = "Eqs/improper_harmonic.jpg">
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</CENTER>
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<P>where X is the improper angle, X0 is its equilibrium value, and K is a
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prefactor. Note that the usual 1/2 factor is included in K.
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</P>
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<P>The following coefficients must be defined for each improper type via the
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<A HREF = "improper_coeff.html">improper_coeff</A> command as in the example above, or in
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the data file or restart files read by the <A HREF = "read_data.html">read_data</A>
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or <A HREF = "read_restart.html">read_restart</A> commands:
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</P>
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<UL><LI>K (energy/radian^2)
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<LI>X0 (degrees)
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</UL>
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<P>X0 is specified in degrees, but LAMMPS converts it to radians
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internally; hence the units of K are in energy/radian^2.
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</P>
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2006-09-28 03:12:31 +08:00
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<P><B>Restrictions:</B> none
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2006-09-22 00:22:34 +08:00
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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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