.. 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 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 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.

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.

----------

.. _Tuckerman2:

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