Source code for ase.cluster.octahedron

"""
Function-like objects that creates cubic clusters.
"""

import numpy as np

from ase.cluster.cubic import FaceCenteredCubic
from ase.cluster.compounds import L1_2

[docs]def Octahedron(symbol, length, cutoff=0, latticeconstant=None, alloy=False): """ Returns Face Centered Cubic clusters of the octahedral class depending on the choice of cutoff. ============================ ======================= Type Condition ============================ ======================= Regular octahedron cutoff = 0 Truncated octahedron cutoff > 0 Regular truncated octahedron length = 3 * cutoff + 1 Cuboctahedron length = 2 * cutoff + 1 ============================ ======================= Parameters: symbol: string or sequence of int The chemical symbol or atomic number of the element(s). length: int Number of atoms on the square edges of the complete octahedron. cutoff (optional): int Number of layers cut at each vertex. latticeconstant (optional): float The lattice constant. If not given, then it is extracted form ase.data. alloy (optional): bool If true the L1_2 structure is used. Default is False. """ # Check length and cutoff if length < 2: raise ValueError("The length must be greater than one.") if cutoff < 0 or length < 2 * cutoff + 1: raise ValueError("The cutoff must fulfill: > 0 and <= (length - 1) / 2.") # Create cluster surfaces = [(1,1,1), (1,0,0)] if length % 2 == 0: center = np.array([0.5, 0.5, 0.5]) layers = [length/2, length - 1 - cutoff] else: center = np.array([0.0, 0.0, 0.0]) layers = [(length - 1)/2, length - 1 - cutoff] if not alloy: return FaceCenteredCubic(symbol, surfaces, layers, latticeconstant, center) else: return L1_2(symbol, surfaces, layers, latticeconstant, center)