"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

:line

compute ke/atom/eff command :h3

[Syntax:]

compute ID group-ID ke/atom/eff :pre

ID, group-ID are documented in "compute"_compute.html command
ke/atom/eff = style name of this compute command :ul

[Examples:]

compute 1 all ke/atom/eff :pre

[Description:]

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 "electronic force field"_pair_eff.html.

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.

There is a subtle difference between the quantity calculated by this
compute and the kinetic energy calculated by the {ke} or {etotal}
keyword used in thermodynamic output, as specified by the
"thermo_style"_thermo_style.html command. For this compute, kinetic
energy is "translational" plus electronic "radial" kinetic energy,
calculated by the simple formula above. For thermodynamic output, the
{ke} 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.

IMPORTANT NOTE: The temperature in eFF should be monitored via the
"compute temp/eff"_compute_temp_eff.html command, which can be printed
with thermodynamic output by using the
"thermo_modify"_thermo_modify.html command, as shown in the following
example:

compute         effTemp all temp/eff
thermo_style    custom step etotal pe ke temp press 
thermo_modify   temp effTemp :pre
 
The value of the kinetic energy will be 0.0 for atoms (nuclei or
electrons) not in the specified compute group.

[Output info:]

This compute calculates a scalar quantity for each atom, which can be
accessed by any command that uses per-atom computes as input.  See
"this section"_Section_howto.html#4_15 for an overview of LAMMPS
output options.

The per-atom vector values will be in energy "units"_units.html.

[Restrictions:]

This compute is part of the "user-eff" package.  It is only enabled if
LAMMPS was built with that package.  See the "Making
LAMMPS"_Section_start.html#2_3 section for more info.

[Related commands:]

"dump custom"_dump.html

[Default:] none
