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85 lines
3.2 KiB
85 lines
3.2 KiB
2 years ago
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"""Function-like object creating triclinic lattices.
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The following lattice creator is defined:
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Triclinic
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"""
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from ase.lattice.bravais import Bravais
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import numpy as np
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from ase.data import reference_states as _refstate
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class TriclinicFactory(Bravais):
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"A factory for creating triclinic lattices."
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# The name of the crystal structure in ChemicalElements
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xtal_name = "triclinic"
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# The natural basis vectors of the crystal structure
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int_basis = np.array([[1, 0, 0],
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[0, 1, 0],
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[0, 0, 1]])
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basis_factor = 1.0
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# Converts the natural basis back to the crystallographic basis
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inverse_basis = np.array([[1, 0, 0],
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[0, 1, 0],
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[0, 0, 1]])
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inverse_basis_factor = 1.0
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def get_lattice_constant(self):
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"Get the lattice constant of an element with triclinic crystal structure."
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if _refstate[self.atomicnumber]['symmetry'] != self.xtal_name:
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raise ValueError(('Cannot guess the %s lattice constant of'
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+ ' an element with crystal structure %s.')
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% (self.xtal_name,
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_refstate[self.atomicnumber]['symmetry']))
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return _refstate[self.atomicnumber].copy()
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def make_crystal_basis(self):
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"Make the basis matrix for the crystal unit cell and the system unit cell."
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lattice = self.latticeconstant
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if isinstance(lattice, type({})):
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a = lattice['a']
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try:
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b = lattice['b']
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except KeyError:
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b = a * lattice['b/a']
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try:
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c = lattice['c']
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except KeyError:
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c = a * lattice['c/a']
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alpha = lattice['alpha']
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beta = lattice['beta']
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gamma = lattice['gamma']
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else:
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if len(lattice) == 6:
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(a, b, c, alpha, beta, gamma) = lattice
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else:
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raise ValueError("Improper lattice constants for triclinic crystal.")
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degree = np.pi / 180.0
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cosa = np.cos(alpha*degree)
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cosb = np.cos(beta*degree)
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sinb = np.sin(beta*degree)
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cosg = np.cos(gamma*degree)
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sing = np.sin(gamma*degree)
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lattice = np.array([[a, 0, 0],
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[b*cosg, b*sing, 0],
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[c*cosb, c*(cosa-cosb*cosg)/sing,
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c*np.sqrt(sinb**2 - ((cosa-cosb*cosg)/sing)**2)]])
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self.latticeconstant = lattice
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self.miller_basis = lattice
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self.crystal_basis = (self.basis_factor *
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np.dot(self.int_basis, lattice))
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self.basis = np.dot(self.directions, self.crystal_basis)
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assert abs(np.dot(lattice[0], lattice[1]) - a*b*cosg) < 1e-5
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assert abs(np.dot(lattice[0], lattice[2]) - a*c*cosb) < 1e-5
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assert abs(np.dot(lattice[1], lattice[2]) - b*c*cosa) < 1e-5
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assert abs(np.dot(lattice[0], lattice[0]) - a*a) < 1e-5
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assert abs(np.dot(lattice[1], lattice[1]) - b*b) < 1e-5
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assert abs(np.dot(lattice[2], lattice[2]) - c*c) < 1e-5
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Triclinic = TriclinicFactory()
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