magpy.geometry.arkus module

Coordinates for Arkus cluster geometries.

This module contains the coordinates of particles arranged into Arkus cluster geometries of varying size. Arkus clusters are minimum energy clusters that represent tightly packed clusters of spherical particles. Their definition (and name) are derived from:

N. Arkus, V. N. Manoharan, and M. P. Brenner, Phys. Rev. Lett. 103, 118303 (2009). http://dx.doi.org/10.1103/PhysRevLett.103.118303

Clusters of 1-5 particles have only one possible arrangement. Clusters of 6 or more particles have a variety of different configurations, which are accessed using a configuration id. The available configuration ranges are:

  • 1-5 particles: [0]
  • 6 particles: [0-1]
  • 7 particles: [0-5]
  • 8 particles; [0-12]

The coordinates of the particles within the cluster are normalised to a unit distance between each pair (where possible). The distance between the particles can be controlled by multiplying by a scaling factor.

magpy.geometry.arkus.ARKUS

dict – a dictionary containing the geometries of Arkus clusters of 1-8 particles. The dictionary is accessed ARKUS[n_particles][configuration_id] and returns an np.ndarray of shape (n_particles,3) containing the coordinates of particles in the cluster.

Examples

>>> ARKUS[1][0]
array([[0,0,0]])
>>> ARKUS[2][0]
array([[0,0,0],
       [0,0,1]])
>>> ARKUS[2][0] * 1e-9 # apply a scaling factor
array([[0,0,0],
       [0,0,1e-9]])