Implement disorder parameter

[Photonsneverrest]

Description

I'm using freud Steinhardt to calculate the disorder parameter as defined by Kawasaki and Onuki (2011) https://doi.org/10.1063/1.3656762. A direct implementation in freud would be nice.

Motivation and Context

The networks I am working with are experimental ones and hence have a degree of disorder of e.g. the node locations compared to a perfect crystal. Moreover there can be differences in the number of neighbors and bond and dihedral angles. The disorder parameter would provide a quantification for the variances of bond orientational order between neighbors.

[tommy-waltmann]

Hi @Photonsneverrest ,

This order parameter seems to give good results for the systems in the paper, however I wonder if there is a simpler way to detect disorder. How is this more useful than using, say, $D = 1 - Q_6$ as a disorder parameter?