Angles between k and k+q

General discussion around the EPW software

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Anish@1991
Posts: 1
Joined: Thu Mar 13, 2025 2:44 pm
Affiliation: Eastern Institute of Technology

Angles between k and k+q

Post by Anish@1991 »

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
Zhe_L
Posts: 15
Joined: Thu Dec 06, 2018 8:54 am
Affiliation:

Re: Angles between k and k+q

Post by Zhe_L »

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
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