[Pw_forum] Spectra from GW and TDDFPT

[jiayudai]

Thanks for your recommendation and reply, mohsen and Giuseppe. So, Giuseppe,  i understand what 's your meaning is
 that the GWW and  TDDFPT in QE distribution (4.3)  can be used for different purposes, but they are both accurate in their fields. In addition, they both have the advantage of efficient computation speed becuase they used different method from the tranditional methods. Is it?

Thanks again.

Jiayu

> Pw_forum at pwscf.org
From: Giuseppe Mattioli <giuseppe.mattioli at mlib.ism.cnr.it>
Subject: Re: [Pw_forum] Spectra from GW and TDDFPT
To: pw_forum at pwscf.org
Message-ID: <201104131432.02080.giuseppe.mattioli at mlib.ism.cnr.it>
Content-Type: text/plain; charset="utf-8"


And, practically speaking, you can obtain corrected (i.e., quasiparticle)
eigenvalues by using GWW, and absorption spectra by using turbo_lanczos, that
is, the GW and TDDFPT current implementations that you find embedded into the
QE (4.3) distribution. Within the above limitations, the computational cost
of both methods can be considered rather low.
HTH

Giuseppe


On Wednesday 13 April 2011 13:59:50 mohsen modaresi wrote:
> Dear Jiayu Dai,
> Prof. R. Godby is one of the most famous scientist who worked on many-body
> theory. i think this lecture should be help full for you.
> {Many-Body Theory and DFT / TDDFT
> Rex Godby"
> http://docs.google.com/viewer?a=v&q=cache:gBMHk9QaO3cJ:www.tddft.org/TDDFT2
>006/2006tddft/docs/school/Godby.pdf+TDDFT+and+GW&hl=en&pid=bl&srcid=ADGEESiq
>9Au0dGZsFvyPUtLL9nEaPg44xzN8NzkJiiguvyAdyTFUpucP8XOKWMyrKammwPLMDfQZncmtgoh8
>NA-PFsRKaUxsRnrdbFId7a7dW2mkkOHqrr4TFgpalZC775KF1njtbF4p&sig=AHIEtbTLv5XgSx5
>m0wfXO3sMV7vzJlgOtg&pli=1
>
> Hope it helps,
>
>
> 2011/4/13 jiayudai <daijiayu at nudt.edu.cn>
>
> > Dear users,
> >
> > It is well known that GW method can give much more accurate band gap
> > since it considers many body interaction, and thus it can give more
> > accurate optical properties. What i am thinking is that what's the
> > difference between the optical properties from TDDFPT and GW. I mean,
> > TDDFPT has the same accuracy as the GW method? or what's the advantage of
> > TDDFPT over the GW except the computationl cost?
> >
> > Thanks a lot.
> >
> > Jiayu
> >
> >
> > -------------------------------------------
> > Jiayu Dai
> > Department of PhysicsNational University of Defense Technology,
> > Changsha, 410073, P R China
> > -----------------------------------------
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