Source code for ase.dft.dos

from math import pi, sqrt

import numpy as np


[docs]class DOS: def __init__(self, calc, width=0.1, window=None, npts=201): """Electronic Density Of States object. calc: calculator object Any ASE compliant calculator object. width: float Width of guassian smearing. window: tuple of two float Use ``window=(emin, emax)``. If not specified, a window big enough to hold all the eigenvalues will be used. npts: int Number of points. """ self.npts = npts self.width = width self.w_k = calc.get_k_point_weights() self.nspins = calc.get_number_of_spins() self.e_skn = np.array([[calc.get_eigenvalues(kpt=k, spin=s) for k in range(len(self.w_k))] for s in range(self.nspins)]) self.e_skn -= calc.get_fermi_level() if window is None: emin = self.e_skn.min() - 5 * self.width emax = self.e_skn.max() + 5 * self.width else: emin, emax = window self.energies = np.linspace(emin, emax, npts)
[docs] def get_energies(self): """Return the array of energies used to sample the DOS. The energies are reported relative to the Fermi level.""" return self.energies
def delta(self, energy): """Return a delta-function centered at 'energy'.""" x = -((self.energies - energy) / self.width)**2 return np.exp(x) / (sqrt(pi) * self.width)
[docs] def get_dos(self, spin=None): """Get array of DOS values. The *spin* argument can be 0 or 1 (spin up or down) - if not specified, the total DOS is returned. """ if spin is None: if self.nspins == 2: # Spin-polarized calculation, but no spin specified - # return the total DOS: return self.get_dos(spin=0) + self.get_dos(spin=1) else: spin = 0 dos = np.zeros(self.npts) for w, e_n in zip(self.w_k, self.e_skn[spin]): for e in e_n: dos += w * self.delta(e) return dos