forked from lijiext/lammps
79 lines
2.7 KiB
HTML
79 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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</CENTER>
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<HR>
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<H3>fix nve/sphere command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>fix ID group-ID nve/sphere
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</PRE>
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<UL><LI>ID, group-ID are documented in <A HREF = "fix.html">fix</A> command
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<LI>nve/sphere = style name of this fix command
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<LI>zero or more keyword/value pairs may be appended
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<LI>keyword = <I>update</I>
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<PRE> <I>update</I> value = <I>dipole</I>
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dipole = update orientation of dipole moment during integration
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</PRE>
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>fix 1 all nve/sphere
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fix 1 all nve/sphere update dipole
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Perform constant NVE integration to update position, velocity, and
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angular velocity for extended spherical particles in the group each
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timestep. V is volume; E is energy. This creates a system trajectory
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consistent with the microcanonical ensemble.
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</P>
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<P>This fix differs from the <A HREF = "fix_nve.html">fix nve</A> command, which
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assumes point particles and only updates their position and velocity.
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</P>
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<P>If the <I>update</I> keyword is used with the <I>dipole</I> value, then the
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orientation of the dipole moment of each particle is also updated
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during the time integration. This option should be used for models
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where a dipole moment is assigned to particles via the
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<A HREF = "dipole.html">dipole</A> command.
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</P>
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<P><B>Restart, fix_modify, output, run start/stop, minimize info:</B>
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</P>
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<P>No information about this fix is written to <A HREF = "restart.html">binary restart
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files</A>. None of the <A HREF = "fix_modify.html">fix_modify</A> options
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are relevant to this fix. No global scalar or vector or per-atom
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quantities are stored by this fix for access by various <A HREF = "Section_howto.html#4_15">output
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commands</A>. No parameter of this fix can be
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used with the <I>start/stop</I> keywords of the <A HREF = "run.html">run</A> command.
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This fix is not invoked during <A HREF = "minimize.html">energy minimization</A>.
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</P>
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<P><B>Restrictions:</B>
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</P>
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<P>This fix requires that atoms store torque and angular velocity (omega)
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as defined by the <A HREF = "atom_style.html">atom_style</A>. It also require they
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store either a per-particle diameter or per-type <A HREF = "shape.html">shape</A>. If
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the <I>dipole</I> keyword is used, then they must store a dipole moment.
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</P>
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<P>All particles in the group must be finite-size spheres. They cannot
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be point particles, nor can they be aspherical.
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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 = "fix_nve.html">fix nve</A>, <A HREF = "fix_nve_asphere.html">fix nve/asphere</A>
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</P>
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<P><B>Default:</B> none
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</P>
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</HTML>
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