1.. index:: angle_style harmonic
2.. index:: angle_style harmonic/intel
3.. index:: angle_style harmonic/kk
4.. index:: angle_style harmonic/omp
5
6angle_style harmonic command
7============================
8
9Accelerator Variants: *harmonic/intel*, *harmonic/kk*, *harmonic/omp*
10
11Syntax
12""""""
13
14.. code-block:: LAMMPS
15
16   angle_style harmonic
17
18Examples
19""""""""
20
21.. code-block:: LAMMPS
22
23   angle_style harmonic
24   angle_coeff 1 300.0 107.0
25
26Description
27"""""""""""
28
29The *harmonic* angle style uses the potential
30
31.. math::
32
33   E = K (\theta - \theta_0)^2
34
35where :math:`\theta_0` is the equilibrium value of the angle, and :math:`K` is a
36prefactor.  Note that the usual 1/2 factor is included in :math:`K`.
37
38The following coefficients must be defined for each angle type via the
39:doc:`angle_coeff <angle_coeff>` command as in the example above, or in
40the data file or restart files read by the :doc:`read_data <read_data>`
41or :doc:`read_restart <read_restart>` commands:
42
43* :math:`K` (energy)
44* :math:`\theta_0` (degrees)
45
46:math:`\theta_0` is specified in degrees, but LAMMPS converts it to
47radians internally; hence :math:`K` is effectively energy per
48radian\^2.
49
50----------
51
52.. include:: accel_styles.rst
53
54----------
55
56Restrictions
57""""""""""""
58
59This angle style can only be used if LAMMPS was built with the
60MOLECULE package.  See the :doc:`Build package <Build_package>` doc
61page for more info.
62
63Related commands
64""""""""""""""""
65
66:doc:`angle_coeff <angle_coeff>`
67
68Default
69"""""""
70
71none
72