forked from lijiext/lammps
56 lines
1.5 KiB
Plaintext
56 lines
1.5 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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compute centro/atom command :h3
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[Syntax:]
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compute ID group-ID centro/atom :pre
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ID, group-ID are documented in "compute"_compute.html command
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centro/atom = style name of this compute command :ul
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[Examples:]
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compute 1 all centro/atom :pre
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[Description:]
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Define a computation that calculates the centro-symmetry parameter for
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each atom in a group. This can be output via the "dump
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custom"_dump.html command.
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This parameter is computed using the following formula from
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"(Kelchner)"_#Kelchner
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:c,image(Eqs/centro_symmetry.jpg)
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where the 12 nearest neighbors are found and Ri and Ri+6 are the
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vectors from the central atom to the opposite pair of nearest
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neighbors. In solid state systems this is a useful measure of the
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local lattice disorder around an atom and can be used to characterize
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whether the atom is part of a perfect lattice, a local defect (e.g. a
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dislocation or stacking fault), or at a surface.
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The neighbor list needed to compute this quantity is constructed each
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time the calculation is performed (i.e. each time a snapshot of atoms
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is dumped). Thus it can be inefficient to compute/dump this quantity
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too frequently or to have multiple compute/dump commands, each of a
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{centro/atom} style.
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[Restrictions:] none
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[Related commands:] none
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[Default:] none
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:line
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:link(Kelchner)
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[(Kelchner)] Kelchner, Plimpton, Hamilton, Phys Rev B, 58, 11085 (1998).
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