[QE-users] asr in dynmat.x

[Lorenzo Bastonero]

Dear Juliana,

In principle at Gamma the acoustic sum rules should only affect the 3 acoustic modes, setting them to 0, and leave the other modes close to their values ( ~< 1/0.1 cm-1).

If you are experiencing huge change in the wavenumber, it may probably be a sign of under converged calculations. Hard to say though w/o inputs/outputs.

HTH,
Lorenzo

********************************
Lorenzo Bastonero

PhD Student
U Bremen Excellence Chair,
Bremen Center for Computational Materials Science,
and MAPEX Center for Materials and Processes

University of Bremen
Faculty of Production Engineering
TAB-Building, Room 3.32
Am Fallturm 1
28359 Bremen, DE

http://www.hmi.uni-bremen.de/

> Il giorno 6 giu 2023, alle ore 15:14, Juliana Maria Abreu Da Silva Morbec <j.morbec at keele.ac.uk> ha scritto:
> 
> Hello.
> 
> I have a question regarding the 'asr' feature in dynmat.x. I am computing Raman spectra of MoS2 bulk and I noticed that asr='simple' and asr='crystal' give different frequencies but similar amplitude for Raman. And asr='crystal' seems to be in better agreement with experiments. How to decide which one to use?
> 
> Thank you,
> 
> Juliana Morbec 
> Lecturer in Physics 
> Keele University, UK 
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