Syntax:
atom_style style args
args = none for any style except hybrid hybrid args = list of one or more styles
Examples:
atom_style bond atom_style full atom_style hybrid eam charge
Description:
Define what style of atoms to use in a simulation. This determines what attributes are associated with the atoms. This command must be used before a simulation is setup via a read_data, read_restart, or create_box command.
Once a style is assigned, it cannot be changed, so use a style general enough to encompass all attributes. E.g. with style bond, angular terms cannot be used or added later to the model. It is OK to use a style more general than needed, though it may be slightly inefficient.
The choice of style affects what quantities are stored by each atom, what quantities are communicated between processors to enable forces to be computed, and what quantities are listed in the data file read by the read_data command.
These are the attributes of each style. All styles store coordinates, velocities, atom IDs and types.
Typical simulations with a single pair potential will use only one of these styles. For cases where multiple pair potentials will be used (see the pair_style hybrid command), it may be necessary to use multiple atom styles. For example, a simulation of biomolecules on a metal surface might require both the eam and full styles. In these cases the hybrid style can be used to list multiple atom styles. Atoms will then store and communicate the union of all quantities implied by the individual styles.
LAMMPS can be extended with new atom styles; see this section.
Restrictions:
This command cannot be used after the simulation box is defined by a read_data or create_box command.
The angle, bond, full, and molecular styles are part of the "molecular" package. The granular style is part of the "granular" package. They are only enabled if LAMMPS was built with that package. See the Making LAMMPS section for more info.
Related commands:
Default: none