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dihedral_style charmm command

Syntax:

dihedral_style charmm 

Examples:

dihedral_style charmm
dihedral_coeff 1 120.0 1 60 0.5 

Description:

The charmm dihedral style uses the potential

See (MacKerell) for a description of the CHARMM force field.

The following coefficients must be defined for each dihedral type via the dihedral_coeff command as in the example above, or in the data file or restart files read by the read_data or read_restart commands:

The weighting factor is applied to pairwise interaction between the 1st and 4th atoms in the dihedral. Note that this weighting factor is unrelated to the weighting factor specified by the special bonds command which applies to all 1-4 interactions in the system. For CHARMM force fields, the latter should typically be set to 0.0, else the 1-4 interactions in a dihedral will be computed twice (once by the pair potential, and once by the dihedral/charmm potential).

Restrictions: none

Related commands:

dihedral_coeff

Default: none


(MacKerell) MacKerell, Bashford, Bellott, Dunbrack, Evanseck, Field, Fischer, Gao, Guo, Ha, et al, J Phys Chem, 102, 3586 (1998).