`
from pyscf.pbc import gto
import numpy as np

cell = gto.Cell()
cell.unit = 'B'
cell.cart = False
basis = {atm: 'gth-dzvp' for atm in ['Si']}
a = (10.2/2)*np.array([[-1, 0 ,1],
[ 0, 1, 1],
[-1, 1, 0]])
cell.build(
atom = '''Si 0, 0, 0; Si 2.55, 2.55, 2.55''',
basis = basis,
pseudo = 'gth-hf-rev',
a = a
)
k_point = np.array([0, 0, 0])
S_GTO = cell.pbc_intor('int1e_ovlp_sph',kpt=k_point)
print(np.diagonal(S_GTO))
print(cell.ao_labels())
`
In the above I am trying to compute the overlap matrix S(k), but I noticed that the values for d-orbitals the values I got are not symmetric around m=0. Why is this not the case?