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compute ackland/atom command

Syntax:

compute ID group-ID ackland/atom 

Examples:

compute 1 all ackland/atom 

Description:

Defines a computation that calculates the local lattice structure according to (Ackland).

In contrast to the centro-symmetry parameter this method is stable against temperature boost, because it is based not on the distance between particles but the angles. Therefore statistical fluctuations are averaged out a little more. A comparison with the Common Neighbor Analysis metric is made in the paper..

The result is a number which is mapped to the following different lattice structures:

The neighbor list needed to compute this quantity is constructed each time the calculation is performed (i.e. each time a snapshot of atoms is dumped). Thus it can be inefficient to compute/dump this quantity too frequently or to have multiple compute/dump commands, each of which computes this quantity.-

Restrictions: none

Related commands:

compute centro/atom

Default: none


(Ackland) Ackland, Jones, Phys Rev B, 73, 054104 (2006).