2006-09-22 00:22:34 +08:00
|
|
|
<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>dihedral_style hybrid command
|
|
|
|
|
</H3>
|
|
|
|
|
<P><B>Syntax:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<PRE>dihedral_style hybrid style1 style2 ...
|
|
|
|
|
</PRE>
|
|
|
|
|
<UL><LI>style1,style2 = list of one or more dihedral styles
|
|
|
|
|
</UL>
|
|
|
|
|
<P><B>Examples:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<PRE>dihedral_style hybrid harmonic helix
|
|
|
|
|
dihedral_coeff 1 harmonic 6.0 1 3
|
|
|
|
|
dihedral_coeff 2 helix 10 10 10
|
|
|
|
|
</PRE>
|
|
|
|
|
<P><B>Description:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<P>The <I>hybrid</I> style enables the use of multiple dihedral styles in one
|
|
|
|
|
simulation. An dihedral style is assigned to each dihedral type. For
|
|
|
|
|
example, dihedrals in a polymer flow (of dihedral type 1) could be
|
|
|
|
|
computed with a <I>harmonic</I> potential and dihedrals in the wall
|
|
|
|
|
boundary (of dihedral type 2) could be computed with a <I>helix</I>
|
|
|
|
|
potential. The assignment of dihedral type to style is made via the
|
|
|
|
|
<A HREF = "dihedral_coeff.html">dihedral_coeff</A> command or in the data file.
|
|
|
|
|
</P>
|
|
|
|
|
<P>In the dihedral_coeff command, the first coefficient sets the dihedral
|
|
|
|
|
style and the remaining coefficients are those appropriate to that
|
2011-06-01 23:21:07 +08:00
|
|
|
style. In the example above, the 2 dihedral_coeff commands set
|
2006-09-22 00:22:34 +08:00
|
|
|
dihedrals of dihedral type 1 to be computed with a <I>harmonic</I>
|
|
|
|
|
potential with coefficients 80.0, 1.2 for K, d, n. Dihedral type 2
|
|
|
|
|
would be computed with a <I>helix</I> potential with coefficients 10.0,
|
|
|
|
|
10.0, 10.0 for A, B, C.
|
|
|
|
|
</P>
|
2011-06-01 23:21:07 +08:00
|
|
|
<P>If dihdral coefficients are specified in the data file read via the
|
|
|
|
|
<A HREF = "read_data.html">read_data</A> command, then the same string,
|
|
|
|
|
e.g. "harmonic" or "helix", must be listed as the 1st argument of each
|
|
|
|
|
line in the "Dihedral Coeffs" section, e.g.
|
|
|
|
|
</P>
|
|
|
|
|
<PRE>1 harmonic 6.0 1 3
|
|
|
|
|
</PRE>
|
|
|
|
|
<P>If the dihedral <I>class2</I> potential is one of the hybrid styles, the
|
|
|
|
|
same rules hold for specifying the additional MiddleBondTorsion,
|
|
|
|
|
EndBondTorsion, AngleTorsion, AngleAngleTorsion, and BondBond13
|
|
|
|
|
coefficients either via the input script or in the data file.
|
|
|
|
|
I.e. "class2" must be added in both cases before the "mbt" or "ebt" or
|
|
|
|
|
"at" or "aat" or "bb13" argument.
|
2007-03-21 04:14:06 +08:00
|
|
|
</P>
|
2009-01-06 06:26:31 +08:00
|
|
|
<P>A dihedral style of <I>none</I> can be specified as the 2nd argument to the
|
2011-06-01 23:21:07 +08:00
|
|
|
dihedral_coeff command or the 1st argument in the data file, if you
|
|
|
|
|
desire to turn off certain dihedral types.
|
2006-09-22 00:22:34 +08:00
|
|
|
</P>
|
2007-06-25 22:36:36 +08:00
|
|
|
<P><B>Restrictions:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<P>This dihedral style can only be used if LAMMPS was built with the
|
|
|
|
|
"molecular" package (which it is by default). See the <A HREF = "Section_start.html#2_3">Making
|
|
|
|
|
LAMMPS</A> section for more info on packages.
|
2006-09-22 00:22:34 +08:00
|
|
|
</P>
|
2008-10-09 22:47:45 +08:00
|
|
|
<P>Unlike other dihedral styles, the hybrid dihedral style does not store
|
|
|
|
|
dihedral coefficient info for individual sub-styles in a <A HREF = "restart.html">binary
|
|
|
|
|
restart files</A>. Thus when retarting a simulation from a
|
|
|
|
|
restart file, you need to re-specify dihedral_coeff commands.
|
|
|
|
|
</P>
|
2006-09-22 00:22:34 +08:00
|
|
|
<P><B>Related commands:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<P><A HREF = "dihedral_coeff.html">dihedral_coeff</A>
|
|
|
|
|
</P>
|
|
|
|
|
<P><B>Default:</B> none
|
|
|
|
|
</P>
|
|
|
|
|
</HTML>
|
