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

[Paolo Giannozzi]

Reporting also here for documentation: I don't think second derivatives 
with linear response are available in QE for the GC-SCF method. I guess 
you may compute them only using "frozen phonons" (finite differences)

Paolo

On 18/06/2025 09:43, ZHANG Yichi wrote:
> 
> 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
> 
> 
> 
> ________________________________________________
> The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare.
> _______________________________________________
> developers mailing list
> developers at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/developers

-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216