ASE Manual Release 3.6.1.2825 CAMd - CampOS Wiki

In Dacapo, the inialwannier keyword can be a list as described below:
ASE Manual, Release 3.6.1.2828
Setup an initial set of Wannier orbitals. initialwannier can set up a starting guess for the Wannier
functions. This is important to speed up convergence in particular for large systems For transition
elements with d electrons you will always find 5 highly localized d-orbitals centered at the atom.
Placing 5 d-like orbitals with a radius of 0.4 Angstroms and center at atom no. 7, and 3 p-like orbitals
with a radius of 0.4 Angstroms and center at atom no. 27 looks like this:
initialwannier = [[[7],2,0.4],[[27],1,0.4]]
Placing only the l=2, m=-2 and m=-1 orbitals at atom no. 7 looks like this:
initialwannier = [[[7],2,-2,0.4],[[7],2,-1,0.4]]
I.e. if you do not specify the m quantum number all allowed values are used. Instead of placing an
orbital at an atom, you can place it at a specified position. For example the following:
initialwannier = [[[0.5,0.5,0.5],0,0.5]]
places an s orbital with radius 0.5 Angstroms at the position (0.5, 0.5, 0.5) in scaled coordinates of
the unit cell.
Note: For calculations using k-points, make sure that the Γ-point is included in the k-point grid. The Wannier
module does not support k-point reduction by symmetry, so you must use the usesymm=False keyword in the
calc, and shift all k-points by a small amount (but not less than 2e-5 in) in e.g. the x direction, before performing
the calculation. If this is not done the symmetry program will still use time-reversal symmetry to reduce the
number of k-points by a factor 2. The shift can be performed like this:
from ase import *
kpts = monkhorst_pack((15, 9, 9)) + [2e-5, 0, 0]
7.22.3 Density of states
Example:
calc = ...
dos = DOS(calc, width=0.2)
d = dos.get_dos()
e = dos.get_energies()
You can plot the result like this:
import pylab as plt
plt.plot(e, d)
plt.xlabel(’energy [eV]’)
plt.ylabel(’DOS’)
plt.show()
7.22. Density Functional Theory 161