Homec4science
Diffusion lammps (efficient_neuronet) Browse

lammps/doc/compute_ke_atom_eff.html
3de59dbf5839efficient_neuronet

Last Change
Raw File

compute_ke_atom_eff.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>compute ke/atom/eff command
</H3>
<P><B>Syntax:</B>
</P>
<PRE>compute ID group-ID ke/atom/eff
</PRE>
<UL><LI>ID, group-ID are documented in <A HREF = "compute.html">compute</A> command
<LI>ke/atom/eff = style name of this compute command
</UL>
<P><B>Examples:</B>
</P>
<PRE>compute 1 all ke/atom/eff
</PRE>
<P><B>Description:</B>
</P>
<P>Define a computation that calculates the per-atom translational
(nuclei and electrons) and radial kinetic energy (electron only) in a
group. The particles are assumed to be nuclei and electrons modeled
with the <A HREF = "pair_eff.html">electronic force field</A>.
</P>
<P>The kinetic energy for each nucleus is computed as 1/2 m v^2, where m
corresponds to the corresponding nuclear mass, and the kinetic energy
for each electron is computed as 1/2 (me v^2 + 3/4 me s^2), where me
and v correspond to the mass and translational velocity of each
electron, and s to its radial velocity, respectively.
</P>
<P>There is a subtle difference between the quantity calculated by this
compute and the kinetic energy calculated by the <I>ke</I> or <I>etotal</I>
keyword used in thermodynamic output, as specified by the
<A HREF = "thermo_style.html">thermo_style</A> command. For this compute, kinetic
energy is "translational" plus electronic "radial" kinetic energy,
calculated by the simple formula above. For thermodynamic output, the
<I>ke</I> keyword infers kinetic energy from the temperature of the system
with 1/2 Kb T of energy for each (nuclear-only) degree of freedom in
eFF.
</P>
<P>IMPORTANT NOTE: The temperature in eFF should be monitored via the
<A HREF = "compute_temp_eff.html">compute temp/eff</A> command, which can be printed
with thermodynamic output by using the
<A HREF = "thermo_modify.html">thermo_modify</A> command, as shown in the following
example:
</P>
<PRE>compute effTemp all temp/eff
thermo_style custom step etotal pe ke temp press
thermo_modify temp effTemp
</PRE>
<P>The value of the kinetic energy will be 0.0 for atoms (nuclei or
electrons) not in the specified compute group.
</P>
<P><B>Output info:</B>
</P>
<P>This compute calculates a scalar quantity for each atom, which can be
accessed by any command that uses per-atom computes as input. See
<A HREF = "Section_howto.html#howto_15">Section_howto 15</A> for an overview of
LAMMPS output options.
</P>
<P>The per-atom vector values will be in energy <A HREF = "units.html">units</A>.
</P>
<P><B>Restrictions:</B>
</P>
<P>This compute is part of the USER-EFF package. It is only enabled if
LAMMPS was built with that package. See the <A HREF = "Section_start.html#start_3">Making
LAMMPS</A> section for more info.
</P>
<P><B>Related commands:</B>
</P>
<P><A HREF = "dump.html">dump custom</A>
</P>
<P><B>Default:</B> none
</P>
</HTML>
c4science · Help