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>bond_coeff command
|
|
|
|
|
</H3>
|
|
|
|
|
<P><B>Syntax:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<PRE>bond_coeff N args
|
|
|
|
|
</PRE>
|
2006-09-29 03:47:07 +08:00
|
|
|
<UL><LI>N = bond type (see asterisk form below)
|
2006-09-22 00:22:34 +08:00
|
|
|
<LI>args = coefficients for one or more bond types
|
|
|
|
|
</UL>
|
|
|
|
|
<P><B>Examples:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<PRE>bond_coeff 5 80.0 1.2
|
|
|
|
|
bond_coeff * 30.0 1.5 1.0 1.0
|
|
|
|
|
bond_coeff 1*4 30.0 1.5 1.0 1.0
|
|
|
|
|
bond_coeff 1 harmonic 200.0 1.0
|
|
|
|
|
</PRE>
|
|
|
|
|
<P><B>Description:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<P>Specify the bond force field coefficients for one or more bond types.
|
|
|
|
|
The number and meaning of the coefficients depends on the bond style.
|
|
|
|
|
Bond coefficients can also be set in the data file read by the
|
|
|
|
|
<A HREF = "read_data.html">read_data</A> command or in a restart file.
|
|
|
|
|
</P>
|
|
|
|
|
<P>N can be specified in one of two ways. An explicit numeric value can
|
2006-09-29 03:47:07 +08:00
|
|
|
be used, as in the 1st example above. Or a wild-card asterisk can be
|
2006-09-22 00:22:34 +08:00
|
|
|
used to set the coefficients for multiple bond types. This takes the
|
|
|
|
|
form "*" or "*n" or "n*" or "m*n". If N = the number of bond types,
|
2006-09-29 03:47:07 +08:00
|
|
|
then an asterisk with no numeric values means all types from 1 to N. A
|
|
|
|
|
leading asterisk means all types from 1 to n (inclusive). A trailing
|
|
|
|
|
asterisk means all types from n to N (inclusive). A middle asterisk
|
2006-09-22 00:22:34 +08:00
|
|
|
means all types from m to n (inclusive).
|
|
|
|
|
</P>
|
|
|
|
|
<P>Note that using a bond_coeff command can override a previous setting
|
|
|
|
|
for the same bond type. For example, these commands set the coeffs
|
|
|
|
|
for all bond types, then overwrite the coeffs for just bond type 2:
|
|
|
|
|
</P>
|
|
|
|
|
<PRE>bond_coeff * 100.0 1.2
|
|
|
|
|
bond_coeff 2 200.0 1.2
|
|
|
|
|
</PRE>
|
|
|
|
|
<P>A line in a data file that specifies bond coefficients uses the exact
|
|
|
|
|
same format as the arguments of the bond_coeff command in an input
|
2006-09-29 03:47:07 +08:00
|
|
|
script, except that wild-card asterisks should not be used since
|
2006-09-22 00:22:34 +08:00
|
|
|
coefficients for all N types must be listed in the file. For example,
|
|
|
|
|
under the "Bond Coeffs" section of a data file, the line that
|
|
|
|
|
corresponds to the 1st example above would be listed as
|
|
|
|
|
</P>
|
|
|
|
|
<PRE>5 80.0 1.2
|
|
|
|
|
</PRE>
|
|
|
|
|
<HR>
|
|
|
|
|
|
|
|
|
|
<P>Here is an alphabetic list of bond styles defined in LAMMPS. Click on
|
|
|
|
|
the style to display the formula it computes and coefficients
|
2012-04-06 22:28:14 +08:00
|
|
|
specified by the associated <A HREF = "bond_coeff.html">bond_coeff</A> command.
|
|
|
|
|
</P>
|
|
|
|
|
<P>Note that here are also additional bond styles submitted by users
|
|
|
|
|
which are included in the LAMMPS distribution. The list of these with
|
|
|
|
|
links to the individual styles are given in the bond section of <A HREF = "Section_commands.html#cmd_5">this
|
|
|
|
|
page</A>.
|
2006-09-22 00:22:34 +08:00
|
|
|
</P>
|
2007-02-10 05:37:30 +08:00
|
|
|
<UL><LI><A HREF = "bond_none.html">bond_style none</A> - turn off bonded interactions
|
|
|
|
|
<LI><A HREF = "bond_hybrid.html">bond_style hybrid</A> - define multiple styles of bond interactions
|
2006-09-22 00:22:34 +08:00
|
|
|
</UL>
|
2009-03-25 04:05:27 +08:00
|
|
|
<UL><LI><A HREF = "bond_class2.html">bond_style class2</A> - COMPASS (class 2) bond
|
2007-02-10 05:37:30 +08:00
|
|
|
<LI><A HREF = "bond_fene.html">bond_style fene</A> - FENE (finite-extensible non-linear elastic) bond
|
|
|
|
|
<LI><A HREF = "bond_fene_expand.html">bond_style fene/expand</A> - FENE bonds with variable size particles
|
|
|
|
|
<LI><A HREF = "bond_harmonic.html">bond_style harmonic</A> - harmonic bond
|
|
|
|
|
<LI><A HREF = "bond_morse.html">bond_style morse</A> - Morse bond
|
|
|
|
|
<LI><A HREF = "bond_nonlinear.html">bond_style nonlinear</A> - nonlinear bond
|
2009-08-11 04:13:44 +08:00
|
|
|
<LI><A HREF = "bond_quartic.html">bond_style quartic</A> - breakable quartic bond
|
|
|
|
|
<LI><A HREF = "bond_table.html">bond_style table</A> - tabulated by bond length
|
2006-09-22 00:22:34 +08:00
|
|
|
</UL>
|
|
|
|
|
<HR>
|
|
|
|
|
|
|
|
|
|
<P><B>Restrictions:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<P>This command must come after the simulation box is defined by a
|
|
|
|
|
<A HREF = "read_data.html">read_data</A>, <A HREF = "read_restart.html">read_restart</A>, or
|
|
|
|
|
<A HREF = "create_box.html">create_box</A> command.
|
|
|
|
|
</P>
|
|
|
|
|
<P>A bond style must be defined before any bond coefficients are set,
|
|
|
|
|
either in the input script or in a data file.
|
|
|
|
|
</P>
|
|
|
|
|
<P><B>Related commands:</B>
|
|
|
|
|
</P>
|
|
|
|
|
<P><A HREF = "bond_style.html">bond_style</A>
|
|
|
|
|
</P>
|
|
|
|
|
<P><B>Default:</B> none
|
|
|
|
|
</P>
|
|
|
|
|
</HTML>
|
