11.4. Pair styles

Classes that compute pairwise interactions are derived from the Pair class. In LAMMPS, pairwise calculation include many-body potentials such as EAM or Tersoff where particles interact without a static bond topology. New styles can be created to add new pair potentials to LAMMPS.

Pair_lj_cut.cpp is a simple example of a Pair class, though it includes some optional methods to enable its use with rRESPA.

Here is a brief description of the class methods in pair.h:

compute workhorse routine that computes pairwise interactions
settings reads the input script line with arguments you define
coeff set coefficients for one i,j type pair
init_one perform initialization for one i,j type pair
init_style initialization specific to this pair style
write & read_restart write/read i,j pair coeffs to restart files
write & read_restart_settings write/read global settings to restart files
single force and energy of a single pairwise interaction between 2 atoms
compute_inner/middle/outer versions of compute used by rRESPA

The inner/middle/outer routines are optional.