improper_harmonic.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>improper_style harmonic command
	</H3>
	<P><B>Syntax:</B>
	</P>
	<PRE>improper_style harmonic
	</PRE>
	<P><B>Examples:</B>
	</P>
	<PRE>improper_style harmonic
	improper_coeff 1 100.0 0
	</PRE>
	<P><B>Description:</B>
	</P>
	<P>The <I>harmonic</I> improper style uses the potential
	</P>
	<CENTER><IMG SRC = "Eqs/improper_harmonic.jpg">
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	<P>where X is the improper angle, X0 is its equilibrium value, and K is a
	prefactor. Note that the usual 1/2 factor is included in K.
	</P>
	<P>The following coefficients must be defined for each improper type via the
	<A HREF = "improper_coeff.html">improper_coeff</A> command as in the example above, or in
	the data file or restart files read by the <A HREF = "read_data.html">read_data</A>
	or <A HREF = "read_restart.html">read_restart</A> commands:
	</P>
	<UL><LI>K (energy/radian^2)
	<LI>X0 (degrees)
	</UL>
	<P>X0 is specified in degrees, but LAMMPS converts it to radians
	internally; hence the units of K are in energy/radian^2.
	</P>
	<P><B>Restrictions:</B> none
	</P>
	<P><B>Related commands:</B>
	</P>
	<P><A HREF = "improper_coeff.html">improper_coeff</A>
	</P>
	<P><B>Default:</B> none
	</P>
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