mirror of https://github.com/lammps/lammps.git
86 lines
2.8 KiB
Plaintext
86 lines
2.8 KiB
Plaintext
.. index:: compute temp/drude
|
|
|
|
compute temp/drude command
|
|
==========================
|
|
|
|
Syntax
|
|
""""""
|
|
|
|
.. parsed-literal::
|
|
|
|
compute ID group-ID temp/drude
|
|
|
|
* ID, group-ID are documented in :doc:`compute <compute>` command
|
|
* temp/drude = style name of this compute command
|
|
|
|
Examples
|
|
""""""""
|
|
|
|
.. parsed-literal::
|
|
|
|
compute TDRUDE all temp/drude
|
|
|
|
Description
|
|
"""""""""""
|
|
|
|
Define a computation that calculates the temperatures of core-Drude
|
|
pairs. This compute is designed to be used with the
|
|
:doc:`thermalized Drude oscillator model <tutorial_drude>`. Polarizable
|
|
models in LAMMPS are described in :ref:`this Section <howto_25>`.
|
|
|
|
Drude oscillators consist of a core particle and a Drude particle
|
|
connected by a harmonic bond, and the relative motion of these Drude
|
|
oscillators is usually maintained cold by a specific thermostat that
|
|
acts on the relative motion of the core-Drude particle
|
|
pairs. Therefore, because LAMMPS considers Drude particles as normal
|
|
atoms in its default temperature compute (:doc:`compute temp <compute_temp>` command), the reduced temperature of the
|
|
core-Drude particle pairs is not calculated correctly.
|
|
|
|
By contrast, this compute calculates the temperature of the cores
|
|
using center-of-mass velocities of the core-Drude pairs, and the
|
|
reduced temperature of the Drude particles using the relative
|
|
velocities of the Drude particles with respect to their cores.
|
|
Non-polarizable atoms are considered as cores. Their velocities
|
|
contribute to the temperature of the cores.
|
|
|
|
**Output info:**
|
|
|
|
This compute calculates a global scalar (the temperature) and a global
|
|
vector of length 6, which can be accessed by indices 1-6, whose components
|
|
are
|
|
|
|
1. temperature of the centers of mass (temperature units)
|
|
2. temperature of the dipoles (temperature units)
|
|
3. number of degrees of freedom of the centers of mass
|
|
4. number of degrees of freedom of the dipoles
|
|
5. kinetic energy of the centers of mass (energy units)
|
|
6. kinetic energy of the dipoles (energy units)
|
|
|
|
These values can be used by any command that uses global scalar or
|
|
vector values from a compute as input. See :ref:`this section <howto_15>` for an overview of LAMMPS output
|
|
options.
|
|
|
|
Both the scalar value and the first two values of the vector
|
|
calculated by this compute are "intensive". The other 4 vector values
|
|
are "extensive".
|
|
|
|
Restrictions
|
|
""""""""""""
|
|
|
|
|
|
The number of degrees of freedom contributing to the temperature is
|
|
assumed to be constant for the duration of the run unless the
|
|
*fix_modify* command sets the option *dynamic yes*\ .
|
|
|
|
Related commands
|
|
""""""""""""""""
|
|
|
|
:doc:`fix drude <fix_drude>`, :doc:`fix langevin/drude <fix_langevin_drude>`, :doc:`fix drude/transform <fix_drude_transform>`, :doc:`pair_style thole <pair_thole>`, :doc:`compute temp <compute_temp>`
|
|
|
|
**Default:** none
|
|
|
|
|
|
.. _lws: http://lammps.sandia.gov
|
|
.. _ld: Manual.html
|
|
.. _lc: Section_commands.html#comm
|