forked from lijiext/lammps
95 lines
3.6 KiB
Plaintext
95 lines
3.6 KiB
Plaintext
"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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pair_style hybrid command :h3
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[Syntax:]
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pair_style hybrid style1 style2 ... :pre
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style1,style2 = list of one or more pair styles :ul
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[Examples:]
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pair_style hybrid lj/charmm/coul/long 10.0 eam
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pair_coeff 1*2 1*2 eam niu3
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pair_coeff 3 3 lj/cut/coul/cut 1.0 1.0
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pair_coeff 1*2 3 lj/cut 0.5 1.2 :pre
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[Description:]
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The {hybrid} style enables the use of multiple pair styles in one
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simulation. A pair style can be assigned to each pair of atom types
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via the "pair_coeff"_pair_coeff.html command.
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For example, a metal on a LJ surface could be computed where the metal
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atoms interact with each other via a {eam} potential, the surface
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atoms interact with each other via a {lj/cut} potential, and the
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metal/surface interaction is also via a {lj/cut} potential.
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All pair styles that will be used must be listed in the pair_style
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hybrid command (in any order). The name of each sub-style is followed
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by its arguments, as illustrated in the example above.
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In the pair_coeff command, the first coefficient sets the pair style
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and the remaining coefficients are those appropriate to that style.
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For example, consider a simulation with 3 atom types: types 1 and 2
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are Ni atoms, type 3 are LJ atoms with charges. The following
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commands would set up a hybrid simulation:
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pair_style hybrid eam/alloy lj/cut/coul/cut 10.0 lj/cut 8.0
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pair_coeff * * eam/alloy nialhjea 1 1 0
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pair_coeff 3 3 lj/cut/coul/cut 1.0 1.0
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pair_coeff 1*2 3 lj/cut 0.8 1.1 :pre
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Note that as with any pair_style, coeffs must be defined for all I,J
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interactions. If the sub-style allows for mixing (see the
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"pair_modify"_pair_modify.html command), then I,J interactions between
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atom types which both are assigned to that sub-style do not need to be
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specified. I.e. if atom types 1 and 2 are both computed with {lj/cut}
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and coeffs for 1,1 and 2,2 interactions are specified, then coeffs for
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1,2 interactions will be generated automatically via mixing.
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If the pair_coeff command for a sub-style requires the use of * * as
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atom type arguments (e.g. the {eam/alloy} example above), then it will
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also include trailing arguments which map atom types to elements in
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the potential. These mapping arguments should be specified as 0 if
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the sub-style is not being applied to certain atom types.
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Note that you may also need to use an "atom_style"_atom_style.html
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hybrid command in your input script, if atoms in the simulation will
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have attributes from several atom styles, due to using multiple pair
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potentials.
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[Restrictions:] none
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When using a long-range Coulomic solver (via the
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"kspace_style"_kspace_style command) with pair_style hybrid, one or
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more sub-styles will be of the "long" variety.
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E.g. {lj/cut/coul/long} or {buck/coul/long}. It is OK to have more
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than one sub-style with a "long" component, but you must insure that
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the short-range Coulombic cutoff used by each of these pair styles is
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consistent. Else the long-range Coulombic solve will be inconsistent.
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A pair style of {none} can be specified as an argument to pair_style
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hybrid and the corresponding pair_coeff commands, if you desire to
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turn off pairwise interactions between certain pairs of atom types.
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The hybrid style cannot include any of the {granular} styles in its
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list of styles to use.
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If you use multiple {coul/long} pair styles along with a "kspace
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style"_kspace_style.html, then you should make sure the pairwise
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Coulombic cutoff is the same for all the pair styles.
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[Related commands:]
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"pair_coeff"_pair_coeff.html
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[Default:] none
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