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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pair_coeff command :h3
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[Syntax:]
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pair_coeff I J args :pre
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2008-02-20 05:47:37 +08:00
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I,J = atom types (see asterisk form below)
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2006-09-22 00:22:34 +08:00
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args = coefficients for one or more pairs of atom types :ul
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[Examples:]
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pair_coeff 1 2 1.0 1.0 2.5
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pair_coeff 2 * 1.0 1.0
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pair_coeff 3* 1*2 1.0 1.0 2.5
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pair_coeff * * 1.0 1.0
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pair_coeff * * nialhjea 1 1 2
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pair_coeff * 3 morse.table ENTRY1
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pair_coeff 1 2 lj/cut 1.0 1.0 2.5 (for pair_style hybrid) :pre
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[Description:]
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Specify the pairwise force field coefficients for one or more pairs of
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atom types. The number and meaning of the coefficients depends on the
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pair style. Pair coefficients can also be set in the data file read
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by the "read_data"_read_data.html command or in a restart file.
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I and J can be specified in one of two ways. Explicit numeric values
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can be used for each, as in the 1st example above. I <= J is
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required. LAMMPS sets the coefficients for the symmetric J,I
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interaction to the same values.
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2008-02-20 05:47:37 +08:00
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A wild-card asterisk can be used in place of or in conjunction with the
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2006-09-22 00:22:34 +08:00
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I,J arguments to set the coefficients for multiple pairs of atom
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types. This takes the form "*" or "*n" or "n*" or "m*n". If N = the
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2008-02-20 05:47:37 +08:00
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number of atom types, then an asterisk with no numeric values means all
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types from 1 to N. A leading asterisk means all types from 1 to n
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(inclusive). A trailing asterisk means all types from n to N
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(inclusive). A middle asterisk means all types from m to n
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2006-09-22 00:22:34 +08:00
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(inclusive). Note that only type pairs with I <= J are considered; if
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2008-02-20 05:47:37 +08:00
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asterisks imply type pairs where J < I, they are ignored.
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2006-09-22 00:22:34 +08:00
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Note that a pair_coeff command can override a previous setting for the
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same I,J pair. For example, these commands set the coeffs for all I,J
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pairs, then overwrite the coeffs for just the I,J = 2,3 pair:
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pair_coeff * * 1.0 1.0 2.5
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pair_coeff 2 3 2.0 1.0 1.12 :pre
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A line in a data file that specifies pair coefficients uses the exact
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same format as the arguments of the pair_coeff command in an input
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script, with the exception of the I,J type arguments. In each line of
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the "Pair Coeffs" section of a data file, only a single type I is
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specified, which sets the coefficients for type I interacting with
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type I. This is because the section has exactly N lines, where N =
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2008-02-20 05:47:37 +08:00
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the number of atom types. For this reason, the wild-card asterisk
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2006-09-22 00:22:34 +08:00
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should also not be used as part of the I argument. Thus in a data
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file, the line corresponding to the 1st example above would be listed
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as
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2 1.0 1.0 2.5 :pre
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2007-06-20 20:56:17 +08:00
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For many potentials, if coefficients for type pairs with I != J are
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2008-02-20 05:47:37 +08:00
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not set explicitly by a pair_coeff command, the values are inferred
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2007-06-20 20:56:17 +08:00
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from the I,I and J,J settings by mixing rules; see the
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2007-06-26 08:03:39 +08:00
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"pair_modify"_pair_modify.html command for a discussion. Details on
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this option as it pertains to individual potentials are described on
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the doc page for the potential.
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2006-09-22 00:22:34 +08:00
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:line
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Here is an alphabetic list of pair styles defined in LAMMPS. Click on
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the style to display the formula it computes, arguments specified in
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the pair_style command, and coefficients specified by the associated
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"pair_coeff"_pair_coeff.html command:
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2009-11-05 06:12:52 +08:00
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"pair_style hybrid"_pair_hybrid.html - multiple styles of pairwise interactions
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2007-10-03 05:55:02 +08:00
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"pair_style hybrid/overlay"_pair_hybrid.html - multiple styles of superposed pairwise interactions :ul
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2007-06-26 08:03:39 +08:00
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"pair_style airebo"_pair_airebo.html - AI-REBO potential
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2009-06-05 00:56:59 +08:00
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"pair_style born/coul/long"_pair_born.html - Born-Mayer-Huggins with long-range Coulomb
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2007-02-10 05:37:30 +08:00
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"pair_style buck"_pair_buck.html - Buckingham potential
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2008-02-20 05:47:37 +08:00
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"pair_style buck/coul/cut"_pair_buck.html - Buckingham with cutoff Coulomb
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2007-02-10 05:37:30 +08:00
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"pair_style buck/coul/long"_pair_buck.html - Buckingham with long-range Coulomb
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2007-06-20 20:56:17 +08:00
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"pair_style colloid"_pair_colloid.html - integrated colloidal potential
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2007-10-03 05:55:02 +08:00
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"pair_style coul/cut"_pair_coul.html - cutoff Coulombic potential
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2008-02-20 05:47:37 +08:00
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"pair_style coul/debye"_pair_coul.html - cutoff Coulombic potential with Debye screening
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2007-10-03 05:55:02 +08:00
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"pair_style coul/long"_pair_coul.html - long-range Coulombic potential
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2008-10-01 23:02:48 +08:00
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"pair_style dipole/cut"_pair_dipole.html - point dipoles with cutoff
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2007-02-10 05:37:30 +08:00
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"pair_style dpd"_pair_dpd.html - dissipative particle dynamics (DPD)
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2009-11-07 01:05:06 +08:00
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"pair_style dsmc"_pair_dsmc.html - Direct Simulation Monte Carlo (DSMC)
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2007-02-10 05:37:30 +08:00
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"pair_style eam"_pair_eam.html - embedded atom method (EAM)
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2007-10-03 05:55:02 +08:00
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"pair_style eam/opt"_pair_eam.html - optimized version of EAM
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2007-02-10 05:37:30 +08:00
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"pair_style eam/alloy"_pair_eam.html - alloy EAM
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2008-01-19 02:16:21 +08:00
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"pair_style eam/alloy/opt"_pair_eam.html - optimized version of alloy EAM
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2007-02-10 05:37:30 +08:00
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"pair_style eam/fs"_pair_eam.html - Finnis-Sinclair EAM
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2008-01-19 02:16:21 +08:00
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"pair_style eam/fs/opt"_pair_eam.html - optimized version of Finnis-Sinclair EAM
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2007-04-20 07:25:27 +08:00
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"pair_style gayberne"_pair_gayberne.html - Gay-Berne ellipsoidal potential
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2009-08-13 00:45:55 +08:00
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"pair_style gayberne/gpu"_pair_gayberne.html - GPU-enabled Gay-Berne ellipsoidal potential
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2009-01-09 08:14:52 +08:00
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"pair_style gran/hertz/history"_pair_gran.html - granular potential with Hertzian interactions
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"pair_style gran/hooke"_pair_gran.html - granular potential with history effects
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"pair_style gran/hooke/history"_pair_gran.html - granular potential without history effects
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2007-02-10 05:37:30 +08:00
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"pair_style lj/charmm/coul/charmm"_pair_charmm.html - CHARMM potential with cutoff Coulomb
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"pair_style lj/charmm/coul/charmm/implicit"_pair_charmm.html - CHARMM for implicit solvent
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"pair_style lj/charmm/coul/long"_pair_charmm.html - CHARMM with long-range Coulomb
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2007-10-03 05:55:02 +08:00
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"pair_style lj/charmm/coul/long/opt"_pair_charmm.html - optimized version of CHARMM with long-range Coulomb
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2007-02-10 05:37:30 +08:00
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"pair_style lj/class2"_pair_class2.html - COMPASS (class 2) force field with no Coulomb
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"pair_style lj/class2/coul/cut"_pair_class2.html - COMPASS with cutoff Coulomb
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"pair_style lj/class2/coul/long"_pair_class2.html - COMPASS with long-range Coulomb
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"pair_style lj/cut"_pair_lj.html - cutoff Lennard-Jones potential with no Coulomb
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2009-08-13 00:45:55 +08:00
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"pair_style lj/cut/gpu"_pair_lj.html - GPU-enabled version of cutoff LJ
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2007-10-03 05:55:02 +08:00
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"pair_style lj/cut/opt"_pair_lj.html - optimized version of cutoff LJ
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2007-02-10 05:37:30 +08:00
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"pair_style lj/cut/coul/cut"_pair_lj.html - LJ with cutoff Coulomb
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2008-02-20 05:47:37 +08:00
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"pair_style lj/cut/coul/debye"_pair_lj.html - LJ with Debye screening added to Coulomb
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2007-02-10 05:37:30 +08:00
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"pair_style lj/cut/coul/long"_pair_lj.html - LJ with long-range Coulomb
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"pair_style lj/cut/coul/long/tip4p"_pair_lj.html - LJ with long-range Coulomb for TIP4P water
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"pair_style lj/expand"_pair_lj_expand.html - Lennard-Jones for variable size particles
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2008-05-16 04:48:06 +08:00
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"pair_style lj/gromacs"_pair_gromacs.html - GROMACS-style Lennard-Jones potential
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"pair_style lj/gromacs/coul/gromacs"_pair_gromacs.html - GROMACS-style LJ and Coulombic potential
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2007-02-10 05:37:30 +08:00
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"pair_style lj/smooth"_pair_lj_smooth.html - smoothed Lennard-Jones potential
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2009-08-11 04:13:44 +08:00
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"pair_style lj96/cut"_pair_lj96_cut.html - Lennard-Jones 9/6 potential
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2007-10-12 07:52:34 +08:00
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"pair_style lubricate"_pair_lubricate.html - hydrodynamic lubrication forces
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2007-02-10 05:37:30 +08:00
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"pair_style meam"_pair_meam.html - modified embedded atom method (MEAM)
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"pair_style morse"_pair_morse.html - Morse potential
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2008-01-19 02:16:21 +08:00
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"pair_style morse/opt"_pair_morse.html - optimized version of Morse potential
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2008-07-24 07:26:28 +08:00
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"pair_style peri/pmb"_pair_peri_pmb.html - peridynamic PMB potential
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2009-02-07 00:12:07 +08:00
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"pair_style reax"_pair_reax.html - ReaxFF potential
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2007-10-23 05:43:55 +08:00
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"pair_style resquared"_pair_resquared.html - Everaers RE-Squared ellipsoidal potential
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2007-02-10 05:37:30 +08:00
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"pair_style soft"_pair_soft.html - Soft (cosine) potential
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"pair_style sw"_pair_sw.html - Stillinger-Weber 3-body potential
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"pair_style table"_pair_table.html - tabulated pair potential
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"pair_style tersoff"_pair_tersoff.html - Tersoff 3-body potential
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2008-10-01 23:02:48 +08:00
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"pair_style tersoff/zbl"_pair_tersoff.html - Tersoff/ZBL 3-body potential
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2009-11-07 05:01:28 +08:00
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"pair_style yukawa"_pair_yukawa.html - Yukawa potential
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"pair_style yukawa/colloid"_pair_yukawa_colloid.html - screened Yukawa potential for finite-size particles :ul
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2006-09-22 00:22:34 +08:00
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2007-10-03 06:56:45 +08:00
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There are also additional pair styles submitted by users which are
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included in the LAMMPS distribution. The list of these with links to
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the individual styles are given in the pair section of "this
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page"_Section_commands.html#3_5.
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2006-09-22 00:22:34 +08:00
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:line
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[Restrictions:]
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This command must come after the simulation box is defined by a
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"read_data"_read_data.html, "read_restart"_read_restart.html, or
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"create_box"_create_box.html command.
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[Related commands:]
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"pair_style"_pair_style.html, "pair_modify"_pair_modify.html,
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"read_data"_read_data.html, "read_restart"_read_restart.html,
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"pair_write"_pair_write.html
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[Default:] none
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