2006-09-22 00:22:34 +08:00
|
|
|
"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
|
|
|
|
|
|
|
|
|
|
fix efield command :h3
|
|
|
|
|
|
|
|
|
|
[Syntax:]
|
|
|
|
|
|
|
|
|
|
fix ID group-ID efield ex ey ez :pre
|
|
|
|
|
|
|
|
|
|
ID, group-ID are documented in "fix"_fix.html command
|
|
|
|
|
efield = style name of this fix command
|
2010-04-22 06:47:54 +08:00
|
|
|
ex,ey,ez = E-field component values (electric field units)
|
|
|
|
|
any of ex,ey,ez can be a variable (see below) :ul
|
2006-09-22 00:22:34 +08:00
|
|
|
|
|
|
|
|
[Examples:]
|
|
|
|
|
|
2010-04-22 06:47:54 +08:00
|
|
|
fix kick external-field efield 1.0 0.0 0.0
|
|
|
|
|
fix kick external-field efield 0.0 0.0 v_oscillate :pre
|
2006-09-22 00:22:34 +08:00
|
|
|
|
|
|
|
|
[Description:]
|
|
|
|
|
|
|
|
|
|
Add a force F = qE to each charged atom in the group due to an
|
|
|
|
|
external electric field being applied to the system.
|
|
|
|
|
|
2010-04-22 06:47:54 +08:00
|
|
|
Any of the 3 quantities defining the E-field components can be
|
2010-04-27 22:33:02 +08:00
|
|
|
specified as an equal-style or atom-style "variable"_variable.html,
|
|
|
|
|
namely {ex}, {ey}, {ez}. If the value is a variable, it should be
|
2010-08-13 07:10:38 +08:00
|
|
|
specified as v_name, where name is the variable name. In this case,
|
|
|
|
|
the variable will be evaluated each timestep, and its value used to
|
2010-04-27 22:33:02 +08:00
|
|
|
determine the E-field component.
|
2010-04-22 06:47:54 +08:00
|
|
|
|
|
|
|
|
Equal-style variables can specify formulas with various mathematical
|
|
|
|
|
functions, and include "thermo_style"_thermo_style.html command
|
|
|
|
|
keywords for the simulation box parameters and timestep and elapsed
|
|
|
|
|
time. Thus it is easy to specify a time-dependent E-field.
|
|
|
|
|
|
|
|
|
|
Atom-style variables can specify the same formulas as equal-style
|
|
|
|
|
variables but can also include per-atom values, such as atom
|
|
|
|
|
coordinates. Thus it is easy to specify a spatially-dependent E-field
|
|
|
|
|
with optional time-dependence as well.
|
|
|
|
|
|
2007-10-11 06:28:11 +08:00
|
|
|
[Restart, fix_modify, output, run start/stop, minimize info:]
|
2007-06-26 08:03:39 +08:00
|
|
|
|
|
|
|
|
No information about this fix is written to "binary restart
|
|
|
|
|
files"_restart.html. None of the "fix_modify"_fix_modify.html options
|
2010-04-03 00:51:06 +08:00
|
|
|
are relevant to this fix. No global or per-atom quantities are stored
|
|
|
|
|
by this fix for access by various "output
|
2011-08-26 01:01:01 +08:00
|
|
|
commands"_Section_howto.html#howto_15. No parameter of this fix can
|
|
|
|
|
be used with the {start/stop} keywords of the "run"_run.html command.
|
2007-10-11 06:28:11 +08:00
|
|
|
This fix is not invoked during "energy minimization"_minimize.html.
|
2007-06-26 08:03:39 +08:00
|
|
|
|
2006-09-22 00:22:34 +08:00
|
|
|
[Restrictions:] none
|
|
|
|
|
|
|
|
|
|
[Related commands:]
|
|
|
|
|
|
|
|
|
|
"fix addforce"_fix_addforce.html
|
|
|
|
|
|
|
|
|
|
[Default:] none
|
