importCIF

importCIF

importCIF(ciffile, mag_ion, Zaxis = None, Yaxis = None, LS_Coupling = None,
                crystalImage=False, NumIonNeighbors=1, ForceImaginary=False,
                ionL = None, ionS = None, CoordinationNumber = None)

Create a point charge model from a .cif file.

Parameters

• cif_file: cif file location
• mag_ion: which ion to treat as the central magnetic ion
• Zaxis: optional, list [a, b, c] defining the desired z axis for the point charge model (using unit cell axes). If None, the axis with the highest rotational symmetry is chosen.
• Yaxis: optional, list [a, b, c] defining the desired y axis (using unit cell axes). If None, a mirror plane with the normal orthogonal to Zaxis (if one exists) is chosen.
• LS_Coupling: optional, float, spin-orbit coupling of the magnetic ion. If None, PyCrystalField will compute in the J basis. If not None, PyCrystalField will compute in the LS basis.
• crystalImage: optional, boolean, whether to export a sketch of the ligand environment and the defined axes. Default: False.
• NumIonNeighbors: optional, int, number of nearest neighbor groups to include in the point charge model. If the first six nearest neighbors are all oxygen ions, these are considered as a group. If the next nearest neighbors are two Zn ions, these are considered as a group. etc. Default: 1.
• ForceImaginary: optional, boolean, force PyCrystalField to include the -m terms in the point charge model (can be useful for comparing two ion sites with different symmetry). Default: False.
• ionL: if the ion is not a rare earth, must be specified for the LS coupling calculations. Default: None
• ionS = if the ion is not a rare earth, must be specified for the LS coupling calculations. Default: None
• CoordinationNumber = Number of ions to include in the coordination sphere. If this is specified, it will override whatever is put for NumIonNeighbors. If None, PyCrystalField will guess the number of ions in the coordination sphere.

Returns

• Lig: a Ligands object used to make the point charge model. (For most purposes, this can be ignored.)

• PCM: a CFLevels object.

• If multiple possible atomic positions are found in the .cif file, then importCIF will return a list of possibilities: [[Lig0, PCM0], [Lig1, PCM1], [Lig2, PCM2]] where 0 treats all listed sites as atoms, 1 gives atoms in position a, and 2 gives atoms in position b.

Examples:

>>> import PyCrystalField as cef
>>> YTOLig, Yb = cef.importCIF('yto.cif','Yb1')

>>> import PyCrystalField as cef
>>> YTOLig, Yb = cef.importCIF('yto.cif','Yb1', Zaxis = [1,1,0])