86 lines
2.4 KiB
ReStructuredText
86 lines
2.4 KiB
ReStructuredText
.. index:: fix neb/spin
|
|
|
|
fix neb/spin command
|
|
====================
|
|
|
|
Syntax
|
|
""""""
|
|
|
|
.. code-block:: LAMMPS
|
|
|
|
fix ID group-ID neb/spin Kspring
|
|
|
|
* ID, group-ID are documented in :doc:`fix <fix>` command
|
|
* neb/spin = style name of this fix command
|
|
|
|
.. parsed-literal::
|
|
|
|
Kspring = spring constant for parallel nudging force
|
|
(force/distance units or force units, see parallel keyword)
|
|
|
|
Examples
|
|
""""""""
|
|
|
|
.. code-block:: LAMMPS
|
|
|
|
fix 1 active neb/spin 1.0
|
|
|
|
Description
|
|
"""""""""""
|
|
|
|
Add nudging forces to spins in the group for a multi-replica
|
|
simulation run via the :doc:`neb/spin <neb_spin>` command to perform a
|
|
geodesic nudged elastic band (GNEB) calculation for finding the
|
|
transition state.
|
|
Hi-level explanations of GNEB are given with the
|
|
:doc:`neb/spin <neb_spin>` command and on the
|
|
:doc:`Howto replica <Howto_replica>` doc page.
|
|
The fix neb/spin command must be used with the "neb/spin" command and
|
|
defines how inter-replica nudging forces are computed. A GNEB
|
|
calculation is divided in two stages. In the first stage n replicas
|
|
are relaxed toward a MEP until convergence. In the second stage, the
|
|
climbing image scheme is enabled, so that the replica having the highest
|
|
energy relaxes toward the saddle point (i.e. the point of highest energy
|
|
along the MEP), and a second relaxation is performed.
|
|
|
|
The nudging forces are calculated as explained in
|
|
:ref:`(Bessarab) <BessarabB>`).
|
|
See this reference for more explanation about their expression.
|
|
|
|
Restart, fix_modify, output, run start/stop, minimize info
|
|
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
|
|
|
|
No information about this fix is written to :doc:`binary restart files <restart>`. None of the :doc:`fix_modify <fix_modify>` options
|
|
are relevant to this fix. No global or per-atom quantities are stored
|
|
by this fix for access by various :doc:`output commands <Howto_output>`.
|
|
No parameter of this fix can be used with the *start/stop* keywords of
|
|
the :doc:`run <run>` command.
|
|
|
|
The forces due to this fix are imposed during an energy minimization,
|
|
as invoked by the :doc:`minimize <minimize>` command via the
|
|
:doc:`neb/spin <neb_spin>` command.
|
|
|
|
Restrictions
|
|
""""""""""""
|
|
|
|
This command can only be used if LAMMPS was built with the SPIN
|
|
package. See the :doc:`Build package <Build_package>` doc
|
|
page for more info.
|
|
|
|
Related commands
|
|
""""""""""""""""
|
|
|
|
:doc:`neb_spin <neb_spin>`
|
|
|
|
Default
|
|
"""""""
|
|
|
|
none
|
|
|
|
----------
|
|
|
|
.. _BessarabB:
|
|
|
|
**(Bessarab)** Bessarab, Uzdin, Jonsson, Comp Phys Comm, 196,
|
|
335-347 (2015).
|