Syntax:
pair_style hybrid style1 style2 ...
Examples:
pair_style hybrid lj/charmm/coul/long 10.0 eam pair_coeff 1*2 1*2 eam niu3 pair_coeff 3 3 lj/cut/coul/cut 1.0 1.0 pair_coeff 1*2 3 lj/cut 0.5 1.2
Description:
The hybrid style enables the use of multiple pair styles in one simulation. A pair style can be assigned to each pair of atom types via the pair_coeff command.
For example, a metal on a LJ surface could be computed where the metal atoms interact with each other via a eam potential, the surface atoms interact with each other via a lj/cut potential, and the metal/surface interaction is also via a lj/cut potential.
All pair styles that will be used must be listed in the pair_style hybrid command (in any order). The name of each sub-style is followed by its arguments, as illustrated in the example above.
In the pair_coeff command, the first coefficient sets the pair style and the remaining coefficients are those appropriate to that style. For example, consider a simulation with 3 atom types: types 1 and 2 are Ni atoms, type 3 are LJ atoms with charges. The following commands would set up a hybrid simulation:
pair_style hybrid eam/alloy lj/cut/coul/cut 10.0 lj/cut 8.0 pair_coeff * * eam/alloy nialhjea 1 1 0 pair_coeff 3 3 lj/cut/coul/cut 1.0 1.0 pair_coeff 1*2 3 lj/cut 0.8 1.1
Note that as with any pair_style, coeffs must be defined for all I,J interactions. If the sub-style allows for mixing (see the pair_modify command), then I,J interactions between atom types which both are assigned to that sub-style do not need to be specified. I.e. if atom types 1 and 2 are both computed with lj/cut and coeffs for 1,1 and 2,2 interactions are specified, then coeffs for 1,2 interactions will be generated automatically via mixing.
If the pair_coeff command for a sub-style requires the use of * * as atom type arguments (e.g. the eam/alloy example above), then it will also include trailing arguments which map atom types to elements in the potential. These mapping arguments should be specified as 0 if the sub-style is not being applied to certain atom types.
Note that you may also need to use an atom_style hybrid command in your input script, if atoms in the simulation will have attributes from several atom styles, due to using multiple pair potentials.
Restrictions: none
When using a long-range Coulomic solver (via the kspace_style command) with pair_style hybrid, one or more sub-styles will be of the "long" variety. E.g. lj/cut/coul/long or buck/coul/long. It is OK to have more than one sub-style with a "long" component, but you must insure that the short-range Coulombic cutoff used by each of these pair styles is consistent. Else the long-range Coulombic solve will be inconsistent.
A pair style of none can be specified as an argument to pair_style hybrid and the corresponding pair_coeff commands, if you desire to turn off pairwise interactions between certain pairs of atom types.
The hybrid style cannot include any of the granular styles in its list of styles to use.
If you use multiple coul/long pair styles along with a kspace style, then you should make sure the pairwise Coulombic cutoff is the same for all the pair styles.
Related commands:
Default: none