diff --git a/doc/src/bond_special.rst b/doc/src/bond_special.rst index 1b9409be3d..5c560d7986 100644 --- a/doc/src/bond_special.rst +++ b/doc/src/bond_special.rst @@ -26,22 +26,36 @@ Description The *special* bond style can be used to impose weighted Lennard Jones and/or Coloumbic interactions on any two particles in the system. It can be used for cases that cannot be handled in :doc:`special_bonds `, such as -1-5 interactions or hyrbrid simulations that require the use of different -weighting factors for different molecules. +1-5 interactions or complex systems that require the use of different +weighting factors for different molecules. It is a potential of the form: + +.. math:: + + E = w_{LJ} E_{LJ} + w_{Coul}E_{Coul} The following coefficients must be defined for each bond type via the :doc:`bond_coeff ` command as in the example above, or in the data file or restart files read by the :doc:`read_data ` or :doc:`read_restart ` commands: -* `w_lj` weight (0.0 to 1.0) on pairwise Lennard-Jones interactions +* :math:`w_{LJ}` weight (0.0 to 1.0) on pairwise Lennard-Jones interactions -* `w_coul` weight (0.0 to 1.0) on pairwise Coulombic interactions - -This command will typically be used in conjunction with +* :math:`w_{Coul}` weight (0.0 to 1.0) on pairwise Coulombic interactions ---------- +This style has strict requirements on the :doc:`special_bonds ` +setting. 1-2 interactions must have weights of zero. 1-3 interactions must +either have weights of zero or the *angle* setting must be turned on. 1-4 +interactions must have weights of zero or the *dihedral* setting must be turned +on. These requirements ensure that the new bonds created by this style do not +create spurious 1-2, 1-3 or 1-4 interactions. + +This style should be used in conjunction with a regular bond style via +:doc:`bond_style hybrid `. Since it can be used to create +bonded interactions between particles that are further away than usual +(e.g. 1-5 or 1-6 interactions), this style may require an increase in the +communication cutoff via the :doc:`neigh_modify ` command. Restrictions @@ -54,6 +68,6 @@ page for more info. Related commands """""""""""""""" -:doc:`bond_coeff `, :doc:`special_bonds `, +:doc:`bond_coeff `, :doc:`special_bonds ` **Default:** none