Asphericity Parameter [1]

The asphericity parameter \(b\) measures how far the structure deviates from a sphere. Values close to zero indicate a near-spherical shape.

Definition

It is defined as

\[b = \lambda_1 - \frac{1}{2}(\lambda_2 + \lambda_3)\]

where \(\lambda_1 \ge \lambda_2 \ge \lambda_3\) are the eigenvalues of the radius of gyration tensor.

Command line

-as
--asphericityParameter
Calculate \(b\). Optionally provide an output filename.
Default: asphericityParameter.csv

Example

MakroLyzer -xyz polymer.xyz -as myAsphericityOutput.csv

Output

The output file contains one row per frame:

Column

Description

Frame

Frame index in the trajectory

Asphericity Parameter (b)

Asphericity value for the full graph