forked from lijiext/lammps
78 lines
2.7 KiB
HTML
78 lines
2.7 KiB
HTML
<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>pair_style hybrid command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>pair_style hybrid style1 style2 ...
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</PRE>
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<UL><LI>style1,style2 = list of one or more pair styles
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>pair_style hybrid lj/charmm/coul/long 10.0 eam
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pair_coeff 1*2 1*2 eam niu3
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pair_coeff 3 3 lj/cut/coul/cut 1.0 1.0
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pair_coeff 1*2 3 lj/cut 0.5 1.2
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>The <I>hybrid</I> style enables the use of multiple pair styles in one
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simulation. A pair style can be assigned to each pair of atom types
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via the <A HREF = "pair_coeff.html">pair_coeff</A> command.
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</P>
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<P>For example, a metal on a LJ surface could be computed where the metal
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atoms interact with each other via a <I>eam</I> potential, the surface
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atoms interact with each other via a <I>lj/cut</I> potential, and the
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metal/surface interaction is also via a <I>lj/cut</I> potential.
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</P>
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<P>All pair styles that will be used must be listed in the pair_style
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hybrid command (in any order). The name of each sub-style is followed
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by its arguments, as illustrated in the example above.
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</P>
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<P>In the pair_coeff command, the first coefficient sets the pair style
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and the remaining coefficients are those appropriate to that style.
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For example, consider a simulation with 3 atom types: types 1 and 2
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are Ni atoms, type 3 are LJ atoms with charges. The following
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commands would set up the hybrid simulation:
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</P>
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<PRE>atom_style hybrid eam charge
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pair_style hybrid eam lj/cut/coul/cut 10.0 lj/cut 8.0
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pair_coeff 1*2 1*2 eam niu3
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pair_coeff 3 3 lj/cut/coul/cut 1.0 1.0
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pair_coeff 1*2 3 lj/cut 0.5 1.2
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</PRE>
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<P>The <A HREF = "atom_style.html">atom_style</A> hybrid command is needed because
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atoms in the simulation will have both EAM and charge attributes.
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</P>
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<P><B>Restrictions:</B> none
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</P>
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<P>When using a long-range Coulomic solver (via the
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<A HREF = "kspace_style">kspace_style</A> command) with pair_style hybrid, one or
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more sub-styles will be of the "long" variety.
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E.g. <I>lj/cut/coul/long</I> or <I>buck/coul/long</I>. It is OK to have more
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than one sub-style with a "long" component, but you must insure that
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the short-range Coulombic cutoff used by each of these pair styles is
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consistent. Else the long-range Coulombic solve will be inconsistent.
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</P>
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<P>The hybrid style cannot include any of the <I>granular</I> styles in its
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list of styles to use. Only one <I>coul/long</I> style can be used in the
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list of hybrid styles.
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "pair_coeff.html">pair_coeff</A>
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</P>
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<P><B>Default:</B> none
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</P>
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