Algorithm 5 Compute f_ki

1:

f_ki = 0

2:

for n, l, (m ≥ 0) do

3:

 for k ← neighbors of atom i do

4:

  \({{\bf{f}}}_{ki}\!+\!=(2-{\delta }_{m0}){\rm{Re}}\left(\right.{\omega }_{i{\mu }_{k}nlm}{\nabla }_{k}{\phi }_{{\mu }_{k}{\mu }_{i}nlm}({{\bf{r}}}_{ki})\left)\right.\)

5:

 end for

6:

end for