forked from lijiext/lammps
79 lines
2.7 KiB
HTML
79 lines
2.7 KiB
HTML
<HTML>
|
|
<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>
|
|
</CENTER>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<HR>
|
|
|
|
<H3>improper_style command
|
|
</H3>
|
|
<P><B>Syntax:</B>
|
|
</P>
|
|
<PRE>improper_style style
|
|
</PRE>
|
|
<UL><LI>style = <I>none</I> or <I>hybrid</I> or <I>class2</I> or <I>cvff</I> or <I>harmonic</I>
|
|
</UL>
|
|
<P><B>Examples:</B>
|
|
</P>
|
|
<PRE>improper_style harmonic
|
|
improper_style cvff
|
|
improper_style hybrid cvff harmonic
|
|
</PRE>
|
|
<P><B>Description:</B>
|
|
</P>
|
|
<P>Set the formula(s) LAMMPS uses to compute improper interactions
|
|
between quadruplets of atoms, which remain in force for the duration
|
|
of the simulation. The list of improper quadruplets is read in by a
|
|
<A HREF = "read_data.html">read_data</A> or <A HREF = "read_restart.html">read_restart</A> command
|
|
from a data or restart file.
|
|
</P>
|
|
<P>Hybrid models where impropers are computed using different improper
|
|
potentials can be setup using the <I>hybrid</I> improper style.
|
|
</P>
|
|
<P>The coefficients associated with a improper style can be specified in a
|
|
data or restart file or via the <A HREF = "improper_coeff.html">improper_coeff</A> command.
|
|
</P>
|
|
<P>Note that when both an improper and pair style is defined, the
|
|
<A HREF = "special_bond.html">special_bond</A> command often needs to be used to
|
|
turn off (or weight) the pairwise interactions that would otherwise
|
|
exist between the 4 bonded atoms.
|
|
</P>
|
|
<HR>
|
|
|
|
<P>Here is an alphabetic list of improper styles defined in LAMMPS. Click on
|
|
the style to display the formula it computes and coefficients
|
|
specified by the associated <A HREF = "improper_coeff.html">improper_coeff</A> command:
|
|
</P>
|
|
<UL><LI><A HREF = "improper_style_none.html">improper_style none</A> - turn off improper interactions
|
|
<LI><A HREF = "improper_style_hybrid.html">improper_style hybrid</A> - define multiple styles of improper interactions
|
|
</UL>
|
|
<UL><LI><A HREF = "improper_style_class2.html">improper_style class2</A> - COMPASS (class 2) improper
|
|
<LI><A HREF = "improper_style_cvff.html">improper_style cvff</A> - CVFF improper
|
|
<LI><A HREF = "improper_style_harmonic.html">improper_style harmonic</A> - harmonic improper
|
|
</UL>
|
|
<HR>
|
|
|
|
<P><B>Restrictions:</B>
|
|
</P>
|
|
<P>Improper styles can only be set for atom_style choices that allow
|
|
impropers to be defined.
|
|
</P>
|
|
<P>Improper styles are part of the "molecular" package or other packages
|
|
as noted in their documentation. They are only enabled if LAMMPS was
|
|
built with that package. See the <A HREF = "Section_start.html#2_2">Making
|
|
LAMMPS</A> section for more info.
|
|
</P>
|
|
<P><B>Related commands:</B>
|
|
</P>
|
|
<P><A HREF = "improper_coeff.html">improper_coeff</A>
|
|
</P>
|
|
<P><B>Default:</B>
|
|
</P>
|
|
<PRE>improper_style none
|
|
</PRE>
|
|
</HTML>
|