Dear LIANG Xiongyi,
Some answers:
- Yes, one needs fixed occupations, because the implementation in PH is
for non-resonant Raman scattering; the formalism in metallic systems is
much more involved, there are some recent developments in the Quantum
ESPRESSO Community at least by Michele Lazzeri and Francesco Mauri
- About LDA, I somehow thought that the restriction is lifted in recent
versions (or, one just neglects the error message by commenting it
out...). But I do not know whether for example hybrid functionals would
work/give reasonable results, GGA yes
- If the problem appears in the self-consistent calculation, the problem
is not in the calculation of Raman spectrum. Without more details about
your system (input, pseudo potentials) we can only guess for what you are
calculating, it is difficult to help, sorry
- First one should of course achieve self-consistency, in principle
having an odd number of electrons is not a problem. Whether the phonon
code works with spin-polarised systems, sorry, I do not know but I would
guess so
Greetings,
apsi
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Ari Paavo Seitsonen / [email protected] / http://www.iki.fi/~apsi/
Ecole Normale Supérieure (ENS), Département de Chimie, Paris
Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935
On Wed, 8 Mar 2017, LEUNG Clarence wrote:
Dear QE users,
As far as I know, when using ph.x to calculate raman spectrum. We should use
fixed occupation and LDA in scf, right?
However a error occur (charge is wrong, smearing is needed ) when I use fixed
occupation in scf calculation because of my system is odd electrons.
what should I do to calculate the raman spectrum of odd electron system?
Thanks in advanced!
Best regards,
LIANG Xiongyi
Department of Physics and Materials Science
City University of Hong Kong
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