# Distinguishing noisy crystalline structures using bond orientational order parameters

## TL;DR

This paper improves bond orientational order parameters to better distinguish crystalline structures in noisy environments, enhancing local structure characterization in soft matter studies.

## Contribution

It introduces a simple modification to the neighborhood definition, making bond orientational order parameters more robust and continuous under noisy conditions.

## Key findings

- Enhanced ability to distinguish FCC and BCC structures with noise
- Proposed neighborhood definition improves robustness of order parameters
- Accurate structure identification despite noise presence

## Abstract

The bond orientational order parameters originally introduced by Steinhardt \emph{et. al.} [Phys. Rev. B \textbf{28}, 784 (1983)] are a common tool for local structure characterization in soft matter studies. Recently, Mickel \emph{et. al.} [J. Chem. Phys. \textbf{138}, 044501 (2013)] highlighted problems of the bond orientational order parameters due to the ambiguity of the underlying neighbourhood definition. Here we show the difficulties of distinguish common structures like FCC- and BCC-based structures with the suggested neighbourhood definitions when noise is introduced. We propose a simple improvement to the neighbourhood definition that results in robust and continuous bond orientational order parameters with which we can accurately distinguish crystal structures even when noise is present.