lammps/doc/angle_cosine_delta.txt

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"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)
:line
angle_style cosine/delta command :h3
[Syntax:]
angle_style cosine/delta :pre
[Examples:]
angle_style cosine/delta
angle_coeff 2*4 75.0 100.0 :pre
[Description:]
The {cosine/delta} angle style uses the potential
:c,image(Eqs/angle_cosine_delta.jpg)
where theta0 is the equilibrium value of the angle, and K is a
prefactor. Note that the usual 1/2 factor is included in K.
The following coefficients must be defined for each angle type via the
"angle_coeff"_angle_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:
K (energy)
theta0 (degrees) :ul
Theta0 is specified in degrees, but LAMMPS converts it to radians
internally.
[Restrictions:]
This angle 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#2_3 section for more info on packages.
[Related commands:]
"angle_coeff"_angle_coeff.html, "angle_style
cosine/squared"_angle_cosine_squared.html
[Default:] none