"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Commands_all.html)

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angle_style cross command :h3

[Syntax:]

angle_style cross :pre

[Examples:]

angle_style cross
angle_coeff 1 200.0 100.0 100.0 1.25 1.25 107.0 :pre

[Description:]

The {cross} angle style uses a potential that couples the bond stretches of
a bend with the angle stretch of that bend:

:c,image(Eqs/angle_cross.jpg)

where r12,0 is the rest value of the bond length between atom 1 and 2,
r32,0 is the rest value of the bond length between atom 2 and 2,
and theta0 is the rest value of the angle. KSS is the force constant of
the bond stretch-bond stretch term and KBS0 and KBS1 are the force constants
of the bond stretch-angle stretch terms.

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:

KSS (energy/distance^2)
KBS0 (energy/distance/rad)
KBS1 (energy/distance/rad)
r12,0 (distance)
r32,0 (distance)
theta0 (degrees) :ul

Theta0 is specified in degrees, but LAMMPS converts it to radians
internally; hence the units of KBS0 and KBS1 are in energy/distance/radian.

[Restrictions:]

This angle style can only be used if LAMMPS was built with the
USER_YAFF package.  See the "Build package"_Build_package.html doc
page for more info.

[Related commands:]

"angle_coeff"_angle_coeff.html

[Default:] none

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