Page Menu
Home
c4science
Search
Configure Global Search
Log In
Files
F78767941
compute_ke_atom_eff.html
No One
Temporary
Actions
Download File
Edit File
Delete File
View Transforms
Subscribe
Mute Notifications
Award Token
Subscribers
None
File Metadata
Details
File Info
Storage
Attached
Created
Thu, Aug 22, 21:21
Size
2 KB
Mime Type
text/html
Expires
Sat, Aug 24, 21:21 (2 d)
Engine
blob
Format
Raw Data
Handle
20096641
Attached To
rLAMMPS lammps
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>
Event Timeline
Log In to Comment