angle_style cross command¶
Syntax¶
angle_style cross
Examples¶
angle_style cross
angle_coeff 1 200.0 100.0 100.0 1.25 1.25 107.0
Description¶
The cross angle style uses a potential that couples the bond stretches of a bend with the angle stretch of that bend:
where \(r_{12,0}\) is the rest value of the bond length between atom 1 and 2, \(r_{32,0}\) is the rest value of the bond length between atom 3 and 2, and \(\theta_0\) is the rest value of the angle. \(K_{SS}\) is the force constant of the bond stretch-bond stretch term and \(K_{BS0}\) and \(K_{BS1}\) 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 command as in the example above, or in the data file or restart files read by the read_data or read_restart commands:
\(K_{SS}\) (energy/distance^2)
\(K_{BS0}\) (energy/distance)
\(K_{BS1}\) (energy/distance)
\(r_{12,0}\) (distance)
\(r_{32,0}\) (distance)
\(\theta_0\) (degrees)
\(\theta_0\) is specified in degrees, but LAMMPS converts it to radians internally; hence the \(K_{BS0}\) and \(K_{BS1}\) are effectively energy/distance per radian.
Restrictions¶
This angle style can only be used if LAMMPS was built with the YAFF package. See the Build package doc page for more info.
Default¶
none