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### angle_style cg/cmm command

Syntax:

    angle_style cg/cmm

Examples:

    angle_style cg/cmm
    angle_coeff 1 300.0 107.0 lj9_6 0.4491 3.7130

Description:

The cg/cmm angle style is a combination of the harmonic angle potential,

where theta0 is the equilibrium value of the angle and K a prefactor, with the repulsive part of the non-bonded cg/cmm pair style between the atoms 1 and 3. This angle potential is intended for coarse grained MD simulations with the CMM parametrization using the pair_style cg/cmm. Relative to the pair_style cg/cmm, however, the energy is shifted by epsilon, to avoid sudden jumps. 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 command as in the example above. As with other CMM coarse grained parameters, they cannot be set in the data file, but can be restored from restarts via the read_restart command:

- K (energy/radian^2)
- theta0 (degrees)
- cg_type (string, one of lj9_6, lj12_4, lj12_6)
- epsilon (energy units)
- sigma (distance units)

Theta0 is specified in degrees, but LAMMPS converts it to radians internally; hence the units of K are in energy/radian^2.

Restrictions:

This angle style can only be used if LAMMPS was built with the "user-cg-cmm" package. See the Making LAMMPS section for more info on packages.

Related commands:

angle_coeff, angle_style harmonic, pair_style cg/cmm

Default: none