lammps/doc/angle_style_cosine_squared.txt

54 lines
1.3 KiB
Plaintext

"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/squared command :h3
[Syntax:]
angle_style cosine/squared :pre
[Examples:]
angle_style cosine/squared
angle_coeff 2*4 75.0 100.0 :pre
[Description:]
The {cosine/squared} angle style uses the potential
:c,image(Eqs/angle_cosine_squared.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:]
Angle styles can only be set for atom styles that allow angles to be
defined.
This angle style is part of the "molecular" package. It is only
enabled if LAMMPS was built with that package. See the "Making
LAMMPS"_Section_start.html#2_2 section for more info.
[Related commands:]
"angle_coeff"_angle_coeff.html
[Default:] none