Homec4science
Diffusion lammps (lammm-devel) Browse

lammps/doc/pair_morse.html
b704a82dafc5lammm-devel

Last Change
Raw File

pair_morse.html
View Options

<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>pair_style morse command
</H3>
<H3>pair_style morse/opt command
</H3>
<P><B>Syntax:</B>
</P>
<PRE>pair_style morse cutoff
</PRE>
<UL><LI>cutoff = global cutoff for Morse interactions (distance units)
</UL>
<P><B>Examples:</B>
</P>
<PRE>pair_style morse 2.5
pair_style morse/opt 2.5
pair_coeff * * 100.0 2.0 1.5
pair_coeff 1 1 100.0 2.0 1.5 3.0
</PRE>
<P><B>Description:</B>
</P>
<P>Style <I>morse</I> computes pairwise interactions with the formula
</P>
<CENTER><IMG SRC = "Eqs/pair_morse.jpg">
</CENTER>
<P>Rc is the cutoff.
</P>
<P>The following coefficients must be defined for each pair of atoms
types via the <A HREF = "pair_coeff.html">pair_coeff</A> command as in the examples
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>D0 (energy units)
<LI>alpha (1/distance units)
<LI>r0 (distance units)
<LI>cutoff (distance units)
</UL>
<P>The last coefficient is optional. If not specified, the global morse
cutoff is used.
</P>
<P>Style <I>morse/opt</I> is an optimized version of style <I>morse</I> that should
give identical answers. Depending on system size and the processor
you are running on, it may be 5-25% faster (for the pairwise portion
of the run time).
</P>
<P><B>Restrictions:</B>
</P>
<P>The <I>morse</I> potential does not support the
<A HREF = "pair_modify.hmtl">pair_modify</A> <I>mix</I> option. Coefficients for all i,j
pairs must be specified explicitly.
</P>
<P>The <I>morse/opt</I> style is part of the "opt" package. It is only
enabled if LAMMPS was built with that package. See the <A HREF = "Section_start.html#2_3">Making
LAMMPS</A> section for more info.
</P>
<P><B>Related commands:</B>
</P>
<P><A HREF = "pair_coeff.html">pair_coeff</A>
</P>
<P><B>Default:</B> none
</P>
</HTML>
c4science · Help