.. index:: dihedral_style opls dihedral_style opls command =========================== dihedral_style opls/intel command ================================= dihedral_style opls/kk command ============================== dihedral_style opls/omp command =============================== Syntax """""" .. parsed-literal:: dihedral_style opls Examples """""""" .. parsed-literal:: dihedral_style opls dihedral_coeff 1 1.740 -0.157 0.279 0.00 # CT-CT-CT-CT dihedral_coeff 2 0.000 0.000 0.366 0.000 # CT-CT-CT-HC dihedral_coeff 3 0.000 0.000 0.318 0.000 # HC-CT-CT-HC Description """"""""""" The *opls* dihedral style uses the potential .. image:: Eqs/dihedral_opls.jpg :align: center 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 :ref:`(Watkins) `. The following coefficients must be defined for each dihedral type via the :doc:`dihedral_coeff ` command as in the example above, or in the data file or restart files read by the :doc:`read_data ` or :doc:`read_restart ` commands: * K1 (energy) * K2 (energy) * K3 (energy) * K4 (energy) ---------- 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 ` 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 ` 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 ` when you invoke LAMMPS, or you can use the :doc:`suffix ` command in your input script. See :doc:`Section_accelerate ` of the manual for more instructions on how to use the accelerated styles effectively. ---------- Restrictions """""""""""" This dihedral style can only be used if LAMMPS was built with the MOLECULE package (which it is by default). See the :ref:`Making LAMMPS ` section for more info on packages. Related commands """""""""""""""" :doc:`dihedral_coeff ` **Default:** none ---------- .. _Watkins: **(Watkins)** Watkins and Jorgensen, J Phys Chem A, 105, 4118-4125 (2001). .. _lws: http://lammps.sandia.gov .. _ld: Manual.html .. _lc: Section_commands.html#comm