[QE-developers] Second-order nuclear derivative of GC-DFT

[ZHANG Yichi]

Dear QE developers,

Hello. There is no doubt that QE supports nuclear gradient of GC-DFT, which can be toggled on with the keyword "lgcscf" in "pw.x". I am writing to ask whether QE supports calculating second-order nuclear derivative especially of GC-DFT, for force constants, phonons, etc, in "ph.x". If yes, is it obtained based on finite-difference method, Hellmann-Feynmann theorem or any theory else? Thank you.

Regards

Yichi Zhang
Postgraduate student
Department of Chemistry
The Hong Kong University of Science and Technology
Office 4207, Clearwater Bay, New Territories, Hong Kong
+852 5219 8714

[cid:a1cf5efd-2996-42de-86bb-ac52005c9e53]
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