forked from lijiext/lammps
54 lines
1.3 KiB
Plaintext
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
|
|
|
|
improper_style harmonic command :h3
|
|
|
|
[Syntax:]
|
|
|
|
improper_style harmonic :pre
|
|
|
|
[Examples:]
|
|
|
|
improper_style harmonic
|
|
improper_coeff 1 100.0 0 :pre
|
|
|
|
[Description:]
|
|
|
|
The {harmonic} improper style uses the potential
|
|
|
|
:c,image(Eqs/improper_harmonic.jpg)
|
|
|
|
where X is the improper angle, X0 is its equilibrium value, and K is a
|
|
prefactor. Note that the usual 1/2 factor is included in K.
|
|
|
|
The following coefficients must be defined for each improper type via the
|
|
"improper_coeff"_improper_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/radian^2)
|
|
X0 (degrees) :ul
|
|
|
|
X0 is specified in degrees, but LAMMPS converts it to radians
|
|
internally; hence the units of K are in energy/radian^2.
|
|
|
|
[Restrictions:]
|
|
|
|
Improper styles can only be set for atom styles that allow impropers to be
|
|
defined.
|
|
|
|
This improper 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:]
|
|
|
|
"improper_coeff"_improper_coeff.html
|
|
|
|
[Default:] none
|