forked from lijiext/lammps
77 lines
2.6 KiB
Plaintext
77 lines
2.6 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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create_atoms command :h3
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[Syntax:]
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create_atoms type keyword values ... :pre
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type = atom type (1-N) of atoms to create on a lattice :ulb,l
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zero or more keyword/value pairs may be appended :l
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keyword = {region} or {basis} :l
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{region} value = region-ID
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region-ID = atoms will only be created if contained in the region
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{basis} values = M itype
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M = which basis atom
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itype = atom type (1-N) to assign to the basis atom :pre
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:ule
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[Examples:]
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create_atoms 1
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create_atoms 3 region regsphere
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create_atoms 1 basis 2 5 :pre
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[Description:]
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This command creates atoms on a lattice as an alternative to reading
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in their coordinates via a "read_data"_read_data.html or
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"read_restart"_read_restart.html command. A simulation box must
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already exist, which is typically created via the
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"create_box"_create_box.html command.
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Before using this command, a lattice must be defined using the
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"lattice"_lattice.html command. If a region is not specified, the
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create_atoms command fills the entire simulation box with atoms on the
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lattice. If a region is specified (see the "region"_region.html
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command), then the geometric volume is filled that is inside the
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simulation box and is also consistent with the region volume. Note
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that a region can be specified so that its "volume" is either inside
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or outside a geometric boundary.
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The "lattice"_lattice.html command specifies one or more basis atoms
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in each unit cell. By default, when created, all basis atoms are
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assigned the argument {type} as their atom type. The keyword {basis}
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can be used to override the default for one or more basis atoms and
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assign them a different atom type.
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By using the create_atoms command multiple times (interleaved with
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"lattice"_lattice.html commands specifying different orientations),
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grain boundaries can be created. Using the create_atoms command in
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conjunction with the "delete_atoms"_delete_atoms.html command,
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reasonably complex geometries can be created. The create_atoms
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command can also be used to add atoms to a system previously read in
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from a data or restart file. In all these cases, care should be taken
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to insure that new atoms do not overlap existing atoms
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inappropriately.
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Created atoms are assigned a velocity of 0.0.
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[Restrictions:]
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An "atom_style"_atom_style.html and "lattice"_lattice.html must be
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previously defined to use this command.
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[Related commands:]
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"lattice"_lattice.html, "region"_region.html, "create_box"_create_box.html,
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"read_data"_read_data.html, "read_restart"_read_restart.html
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[Default:] none
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