lammps/doc/dihedral_opls.txt

"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

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dihedral_style opls command :h3
dihedral_style opls/omp command :h3

[Syntax:]

dihedral_style opls :pre

[Examples:]

dihedral_style opls
dihedral_coeff 1 90.0 90.0 90.0 70.0 :pre

[Description:]

The {opls} dihedral style uses the potential

:c,image(Eqs/dihedral_opls.jpg)

Note that the usual 1/2 factor is not included in the K values.

This dihedral potential is used in the OPLS force field and is
described in "(Watkins)"_#Watkins.

The following coefficients must be defined for each dihedral type via the
"dihedral_coeff"_dihedral_coeff.html command as in the example above, or in
the data file or restart files read by the "read_data"_read_data.html
or "read_restart"_read_restart.html commands:

K1 (energy)
K2 (energy)
K3 (energy)
K4 (energy) :ul

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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 "Section_accelerate"_Section_accelerate.html
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 "Making
LAMMPS"_Section_start.html#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 "-suffix command-line
switch"_Section_start.html#start_7 when you invoke LAMMPS, or you can
use the "suffix"_suffix.html command in your input script.

See "Section_accelerate"_Section_accelerate.html of the manual for
more instructions on how to use the accelerated styles effectively.

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[Restrictions:]

This dihedral style can only be used if LAMMPS was built with the
MOLECULAR package (which it is by default).  See the "Making
LAMMPS"_Section_start.html#start_3 section for more info on packages.

[Related commands:]

"dihedral_coeff"_dihedral_coeff.html

[Default:] none

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:link(Watkins)
[(Watkins)] Watkins and Jorgensen, J Phys Chem A, 105, 4118-4125 (2001).