.. index:: fix nvt/sllod/eff

fix nvt/sllod/eff command
=========================

Syntax
""""""

.. code-block:: LAMMPS

   fix ID group-ID nvt/sllod/eff keyword value ...

* ID, group-ID are documented in :doc:`fix <fix>` command
* nvt/sllod/eff = style name of this fix command
* zero or more keyword/value pairs may be appended

  .. parsed-literal::

     keyword = *psllod*
       *psllod* value = *no* or *yes* = use SLLOD or p-SLLOD variant, respectively

* additional thermostat related keyword/value pairs from the :doc:`fix
  nvt/eff <fix_nh_eff>` command may be appended, too.

Examples
""""""""

.. code-block:: LAMMPS

   fix 1 all nvt/sllod/eff temp 300.0 300.0 0.1
   fix 1 all nvt/sllod/eff temp 300.0 300.0 0.1 drag 0.2

Description
"""""""""""

Perform constant NVT integration to update positions and velocities each
timestep for nuclei and electrons in the group for the :doc:`electron
force field <pair_eff>` model, using a Nose/Hoover temperature
thermostat.  V is volume; T is temperature.  This creates a system
trajectory consistent with the canonical ensemble.

The operation of this fix is exactly like that described by the
:doc:`fix nvt/sllod <fix_nvt_sllod>` command, except that the radius and
radial velocity of electrons are also updated and thermostatted.
Likewise the temperature calculated by the fix, using the compute it
creates (as discussed in the :doc:`fix nvt, npt, and nph <fix_nh>` doc
page), is performed with a :doc:`compute temp/deform/eff
<compute_temp_deform_eff>` command (if *peculiar* = *no*) or a
:doc:`compute temp/eff <compute_temp_eff>` command
(if *peculiar* = *yes*) that includes the eFF contribution to
the temperature from the electron radial velocity.

Restart, fix_modify, output, run start/stop, minimize info
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

This fix writes the state of the Nose/Hoover thermostat to
:doc:`binary restart files <restart>`.  See the :doc:`read_restart
<read_restart>` command for info on how to re-specify a fix in an
input script that reads a restart file, so that the operation of the
fix continues in an uninterrupted fashion.

The :doc:`fix_modify <fix_modify>` *temp* option is supported by this
fix.  You can use it to assign a :doc:`compute <compute>` you have
defined to this fix which will be used in its thermostatting
procedure.  The *kick* option is also supported as described by
:doc:`fix nvt/sllod <fix_nvt_sllod>`.

The cumulative energy change in the system imposed by this fix is
included in the :doc:`thermodynamic output <thermo_style>` keywords
*ecouple* and *econserve*.  See the :doc:`thermo_style <thermo_style>`
doc page for details.  Note, as for :doc:`fix nvt/sllod <fix_nvt_sllod>`
this does NOT include the work done to drive the flow, so those values
are expected to change with time.

This fix computes the same global scalar and global vector of
quantities as does the :doc:`fix nvt/eff <fix_nh_eff>` command.

This fix can ramp its target temperature over multiple runs, using the
*start* and *stop* keywords of the :doc:`run <run>` command.  See the
:doc:`run <run>` command for details of how to do this.

This fix is not invoked during :doc:`energy minimization <minimize>`.

Restrictions
""""""""""""

This fix is part of the EFF package.  It is only enabled if
LAMMPS was built with that package.  See the :doc:`Build package <Build_package>` page for more info.

This fix works best without Nose-Hoover chain thermostats, i.e. using
tchain = 1.  Setting tchain to larger values can result in poor
equilibration.

Related commands
""""""""""""""""

:doc:`fix nve/eff <fix_nve_eff>`, :doc:`fix nvt/eff <fix_nh_eff>`, :doc:`fix langevin/eff <fix_langevin_eff>`, :doc:`fix nvt/sllod <fix_nvt_sllod>`, :doc:`fix_modify <fix_modify>`, :doc:`compute temp/deform/eff <compute_temp_deform_eff>`

Default
"""""""

Same as :doc:`fix nvt/eff <fix_nh_eff>`, except *tchain* = 1, *psllod* = *no*,
*peculiar* = *no*, *kick* = *yes*, *integrator* = *reversible*.

----------

.. _Tuckerman2:

**(Tuckerman)** Tuckerman, Mundy, Balasubramanian, Klein, J Chem Phys,
106, 5615 (1997).
