"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 evaporate command :h3

[Syntax:]

fix ID group-ID evaporate N M region-ID seed :pre

ID, group-ID are documented in "fix"_fix.html command
evaporate = style name of this fix command
N = delete atoms every this many timesteps
M = number of atoms to delete each time
region-ID = ID of region within which to perform deletions
seed = random number seed to use for choosing atoms to delete :ul

[Examples:]

fix 1 solvent evaporate 1000 10 surface 49892 :pre

[Description:]

Remove M atoms from the simulation every N steps.  This can be used,
for example, to model evaporation of solvent particles (i.e. drying)
of a system.  Every N steps, the number of atoms in the fix group and
within the specifed region are counted.  M of these are chosen at
random and deleted.  If there are less than M eligible particles, then
all of them are deleted.

Note that you cannot currently delete solvent molecules with this
command, only individual atoms.  If you delete only one atom in a
molecule, an error will result.

Note that neighbor lists are re-built on timesteps that atoms are
removed.  Thus you should not remove atoms too frequently or you will
incur overhead due to the cost of building neighbor lists.

[Restart, fix_modify, output, run start/stop, minimize info:]

No information about this fix is written to "binary restart
files"_restart.html.  None of the "fix_modify"_fix_modify.html options
are relevant to this fix.

The cummulative number of deleted atoms is stored as a scalar quantity
by this fix.  This quantity can be accessed by various "output
commands"_Section_howto.html#4_15.  The scalar value is "intensive".

No parameter of this fix can be used with the {start/stop} keywords of
the "run"_run.html command.  This fix is not invoked during "energy
minimization"_minimize.html.

[Restrictions:] none

[Related commands:]

"fix deposit"_fix_deposit.html

[Default:] none
