2006-09-22 00:22:34 +08:00
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"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
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:link(lws,http://lammps.sandia.gov)
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:link(ld,Manual.html)
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:link(lc,Section_commands.html#comm)
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:line
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dihedral_style charmm command :h3
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[Syntax:]
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dihedral_style charmm :pre
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[Examples:]
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dihedral_style charmm
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dihedral_coeff 1 120.0 1 60 0.5 :pre
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[Description:]
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The {charmm} dihedral style uses the potential
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:c,image(Eqs/dihedral_charmm.jpg)
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2006-09-28 03:12:31 +08:00
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See "(MacKerell)"_#MacKerell for a description of the CHARMM force
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field.
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2006-09-22 00:22:34 +08:00
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The following coefficients must be defined for each dihedral type via the
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"dihedral_coeff"_dihedral_coeff.html command as in the example above, or in
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the data file or restart files read by the "read_data"_read_data.html
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or "read_restart"_read_restart.html commands:
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K (energy)
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n (integer >= 0)
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d (integer value of degrees)
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weighting factor (0.0 to 1.0) :ul
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The weighting factor is applied to pairwise interaction between the
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1st and 4th atoms in the dihedral. Note that this weighting factor is
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unrelated to the weighting factor specified by the "special
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bonds"_doc/special_bonds.html command which applies to all 1-4
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interactions in the system. For CHARMM force fields, the latter
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should typically be set to 0.0, else the 1-4 interactions in a
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dihedral will be computed twice (once by the pair potential, and once
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by the dihedral/charmm potential).
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2006-09-28 03:12:31 +08:00
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[Restrictions:] none
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2006-09-22 00:22:34 +08:00
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[Related commands:]
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"dihedral_coeff"_dihedral_coeff.html
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[Default:] none
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2006-09-28 03:12:31 +08:00
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:line
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:link(MacKerell)
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[(MacKerell)] MacKerell, Bashford, Bellott, Dunbrack, Evanseck, Field,
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Fischer, Gao, Guo, Ha, et al, J Phys Chem, 102, 3586 (1998).
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