"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

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dihedral_style hybrid command :h3

[Syntax:]

dihedral_style hybrid style1 style2 ... :pre

style1,style2 = list of one or more dihedral styles :ul

[Examples:]

dihedral_style hybrid harmonic helix
dihedral_coeff 1 harmonic 6.0 1 3
dihedral_coeff 2 helix 10 10 10 :pre

[Description:]

The {hybrid} style enables the use of multiple dihedral styles in one
simulation.  An dihedral style is assigned to each dihedral type.  For
example, dihedrals in a polymer flow (of dihedral type 1) could be
computed with a {harmonic} potential and dihedrals in the wall
boundary (of dihedral type 2) could be computed with a {helix}
potential.  The assignment of dihedral type to style is made via the
"dihedral_coeff"_dihedral_coeff.html command or in the data file.

In the dihedral_coeff command, the first coefficient sets the dihedral
style and the remaining coefficients are those appropriate to that
style.  In the example above, the 2 dihedral_coeff commands would set
dihedrals of dihedral type 1 to be computed with a {harmonic}
potential with coefficients 80.0, 1.2 for K, d, n.  Dihedral type 2
would be computed with a {helix} potential with coefficients 10.0,
10.0, 10.0 for A, B, C.

If the dihedral {class2} potential is one of the hybrid styles, it
requires additional MiddleBondTorsion, EndBondTorsion, AngleTorsion,
AngleAngleTorsion, and BondBond13 coefficients be specified in the
data file.  These lines must also have an additional "class2" argument
added after the dihedral type.  For dihedral types which are assigned
to other hybrid styles, use the style name (e.g. "harmonic")
appropriate to that style.  The MiddleBondTorsion, etc coeffs for that
dihedral type will then be ignored.

A dihedral style of {none} can be specified as the 2nd argument to the
dihedral_coeff command, if you desire to turn off certain dihedral
types.

[Restrictions:]

This dihedral style can only be used if LAMMPS was built with the
"molecular" package (which it is by default).  See the "Making
LAMMPS"_Section_start.html#2_3 section for more info on packages.

Unlike other dihedral styles, the hybrid dihedral style does not store
dihedral coefficient info for individual sub-styles in a "binary
restart files"_restart.html.  Thus when retarting a simulation from a
restart file, you need to re-specify dihedral_coeff commands.

[Related commands:]

"dihedral_coeff"_dihedral_coeff.html

[Default:] none
