EPW Forum

Dear experts,

If I want to calculate the angles between k and k+q, then should I fold back the k+q vectors in the 1st BZ if it lies outside, or calculate the angles in extended BZ?

Thank you
Anish

Dear Anish,

As you mentioned, "angles between k and k+q" is arbitrary due to the equivalence between k and k + G, G being the reciprocal lattice vector.

However, if it can not be well-defined, it is most likely meaningless for research. So you'd better describe what you're calculating and why you need this angle.

Best,
Zhe