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bond_class2.txt
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.. index:: bond_style class2
bond_style class2 command
=========================
bond_style class2/omp command
=============================
Syntax
""""""
.. parsed-literal::
bond_style class2
Examples
""""""""
.. parsed-literal::
bond_style class2
bond_coeff 1 1.0 100.0 80.0 80.0
Description
"""""""""""
The *class2* bond style uses the potential
.. image:: Eqs/bond_class2.jpg
:align: center
where r0 is the equilibrium bond distance.
See :ref:`(Sun) <Sun>` for a description of the COMPASS class2 force field.
The following coefficients must be defined for each bond type via the
:doc:`bond_coeff <bond_coeff>` command as in the example above, or in
the data file or restart files read by the :doc:`read_data <read_data>`
or :doc:`read_restart <read_restart>` commands:
* R0 (distance)
* K2 (energy/distance^2)
* K3 (energy/distance^3)
* K4 (energy/distance^4)
----------
Styles with a *cuda*, *gpu*, *intel*, *kk*, *omp*, or *opt* suffix are
functionally the same as the corresponding style without the suffix.
They have been optimized to run faster, depending on your available
hardware, as discussed in :doc:`Section_accelerate <Section_accelerate>`
of the manual. The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
issues.
These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
KOKKOS, USER-OMP and OPT packages, respectively. They are only
enabled if LAMMPS was built with those packages. See the :ref:`Making LAMMPS <start_3>` section for more info.
You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the :ref:`-suffix command-line switch <start_7>` when you invoke LAMMPS, or you can
use the :doc:`suffix <suffix>` command in your input script.
See :doc:`Section_accelerate <Section_accelerate>` of the manual for
more instructions on how to use the accelerated styles effectively.
----------
Restrictions
""""""""""""
This bond style can only be used if LAMMPS was built with the CLASS2
package. See the :ref:`Making LAMMPS <start_3>` section
for more info on packages.
Related commands
""""""""""""""""
:doc:`bond_coeff <bond_coeff>`, :doc:`delete_bonds <delete_bonds>`
**Default:** none
----------
.. _Sun:
**(Sun)** Sun, J Phys Chem B 102, 7338-7364 (1998).
.. _lws: http://lammps.sandia.gov
.. _ld: Manual.html
.. _lc: Section_commands.html#comm
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