Usage

This package only provides basic, low level interfaces for reading data rather than performing any analysis.

No unit conversion is carried out - any numerical values returned are simply in the internal unit used by CASTEP. In most cases, they are in the atomic units.

To convert to SI-based units, one can use ase.units:

from castepxbin import castep_bin import read_castep_bin
from ase.units import Hartree

data = read_castep_bin(filename='<path to .castep_bin or .check>')
print("One Ha is {Hartree} eV")

fermi_energy_in_eV = data['fermi_energy'] * Hartree

Supported files

pdos_bin

Stores the weights projected onto atomic orbitals for each band. This file is necessary for constructing projected density of states. This file is only written with pdos_calculate_weights : true in the param file. Use read_pdos_bin to parse this file. It returns a dictionary of arrays.

The arrays are not arranged in the most sensible way and one may want to use reorder_pdos_data to process it so the species, ion number and orbitals are assigned. The compute_pdos function can be used to obtain the projected-density of states, but one needs to supply the eigenvalues (mind the units) and the weighting of the kpoints.

ome_bin

Stores the optical matrix elements from a task : spectral calculation with spectral_task being one of optics, coreless, all.

dome_bin

Stores the diagonal elements of the optical matrix from a task : spectral calculation with spectral_task being dos.

cst_ome

Stores the optical matrix elements from a task : optics calculation.

check

Stores most calculated quantities and can be used for restarting a calculation.

castep_bin

This file is essentially the same as check except it does not include the wave functions.

orbitals

This file is very similar to check but stores wave functions of non-self-consistent field calculations, e.g. those from band structure and density of states calculations with fine sampling grids (task in spectral, bandstructure, and optics). Activated by setting write_orbitals : true in the param file.

Note

Both orbitals and check files can be read with castepxbin.castep_bin.read_castep_bin() function. The wave function will be read so make sure you have enough memory available. At the moment, the packages does not support reading subsets of the wave function.