Syntax:
angle_style charmm
Examples:
angle_style charmm angle_coeff 1 300.0 107.0 50.0 3.0
Description:
The charmm angle style uses the potential
with an additional Urey_Bradley term based on the distance r between the 1st and 3rd atoms in the angle. K, theta0, Kub, and Rub are coefficients defined for each angle type.
See (MacKerell) for a description of the CHARMM force field.
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:
Theta0 is specified in degrees, but LAMMPS converts it to radians internally; hence the units of K are in energy/radian^2.
Restrictions: none
Related commands:
Default: none
(MacKerell) MacKerell, Bashford, Bellott, Dunbrack, Evanseck, Field, Fischer, Gao, Guo, Ha, et al, J Phys Chem, 102, 3586 (1998).