[QE-users] Where and how the "eigendisplacements z" is calculated?

[xin.jin at mail.com]

Thank you very much Paolo. It helps a lot.

Best regards,
Xin

-----Original Message-----
From: Paolo Giannozzi <paolo.giannozzi at uniud.it> 
Sent: January 21, 2023 05:26
To: Quantum ESPRESSO users Forum <users at lists.quantum-espresso.org>
Cc: xin.jin at mail.com
Subject: Re: [QE-users] Where and how the "eigendisplacements z" is calculated?

The normal modes are computed in routine "dyndia.f90", that diagonalizes the dynamical matrix

Paolo

On 20/01/2023 20:38, xin.jin at mail.com wrote:
> 
> Dear colleagues,
> 
> I’m trying to calculate the RamanIR part manually using Matlab. I’m 
> blocked by the z(3*nat,3*nat).
> 
> Can I get the “z” from the *.dyn file (or somewhere else) directly, or 
> do I need additional arrangements for calculation?
> 
> I see in “dynamt_sub.90,” the description  of the subroutine “RamanIR 
> (nat, omega, w2, z, zstar, eps0, dchi_dtau)” right there: “on input: z 
> = eigendisplacements (normalized as <z|M|z>).” I know what this 
> normalization is, but I’m still confused about how and where this 
> eigendisplacement “z” is calculated in PHonon.
> 
> This question may sound fundamental and dumb, but I would greatly 
> appreciate it if someone could explain it a bit more to me.
> 
> Best regards,
> 
> Xin Jin
> 
> Ph.D. in Energy Science and Materials
> 
> Postdoctoral Researcher
> 
> Institut National de la Recherche Scientifique
> 
> - Énergie, Matériaux et Télécommunications (INRS-EMT)
> 
> Address: 1650, Boulevard Lionel Boulet, Varennes, Quebec J3X 1P7, 
> Canada
> 
> 
> _______________________________________________
> The Quantum ESPRESSO community stands by the Ukrainian people and 
> expresses its concerns about the devastating effects that the Russian 
> military offensive has on their country and on the free and peaceful 
> scientific, cultural, and economic cooperation amongst peoples 
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing 
> list users at lists.quantum-espresso.org 
> https://lists.quantum-espresso.org/mailman/listinfo/users

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