Dear Giuseppe,<br />
<br />
I think the current TDDFPT can only work without spin polarization, is it? Besides, i do not know is there any limitation in theory to deal with more k_points and metallic case? In my test, it can not deal with the molecule such as NO2, since it needs the smearing method in the scf calculations.<br />
<br />
Thanks.<br />
<br />
Jiayu<br />
<br />
<br />
From: Giuseppe Mattioli <giuseppe.mattioli@mlib.ism.cnr.it><br />
Subject: Re: [Pw_forum] Spectra from GW and TDDFPT<br />
To: PWSCF Forum <pw_forum@pwscf.org><br />
Message-ID: <201104131649.52909.giuseppe.mattioli@mlib.ism.cnr.it><br />
Content-Type: text/plain; charset="utf-8"<br />
<br />
Dear Jiayu<br />
Yes, it is. With only one additional warning: the TDDFPT code works only at<br />
Gamma (and fixed occupations). It is not designed to deal with periodic<br />
systems where you need k-points, but (in my experience) it works well with<br />
molecules.<br />
<br />
On Wednesday 13 April 2011 15:20:59 jiayudai wrote:<br />
> Thanks for your recommendation and reply, mohsen and Giuseppe. So,<br />
> Giuseppe, i understand what 's your meaning is that the GWW and TDDFPT in<br />
> QE distribution (4.3) can be used for different purposes, but they are<br />
> both accurate in their fields. In addition, they both have the advantage of<br />
> efficient computation speed becuase they used different method from the<br />
> tranditional methods. Is it?<br />
><br />
> Thanks again.<br />
><br />
> Jiayu<br />
><br />
> > Pw_forum@pwscf.org<br />
><br />
> From: Giuseppe Mattioli <giuseppe.mattioli@mlib.ism.cnr.it><br />
> Subject: Re: [Pw_forum] Spectra from GW and TDDFPT<br />
> To: pw_forum@pwscf.org<br />
> Message-ID: <201104131432.02080.giuseppe.mattioli@mlib.ism.cnr.it><br />
> Content-Type: text/plain; charset="utf-8"<br />
><br />
><br />
> And, practically speaking, you can obtain corrected (i.e., quasiparticle)<br />
> eigenvalues by using GWW, and absorption spectra by using turbo_lanczos,<br />
> that is, the GW and TDDFPT current implementations that you find embedded<br />
> into the QE (4.3) distribution. Within the above limitations, the<br />
> computational cost of both methods can be considered rather low.<br />
> HTH<br />
><br />
> Giuseppe<br />
><br />
> On Wednesday 13 April 2011 13:59:50 mohsen modaresi wrote:<br />
> > Dear Jiayu Dai,<br />
> > Prof. R. Godby is one of the most famous scientist who worked on<br />
> > many-body theory. i think this lecture should be help full for you.<br />
> > {Many-Body Theory and DFT / TDDFT<br />
> > Rex Godby"<br />
> > http://docs.google.com/viewer?a=v&q=cache:gBMHk9QaO3cJ:www.tddft.org/TDDF<br />
> >T2<br />
> > 006/2006tddft/docs/school/Godby.pdf+TDDFT+and+GW&hl=en&pid=bl&srcid=ADGEE<br />
> >Siq<br />
> > 9Au0dGZsFvyPUtLL9nEaPg44xzN8NzkJiiguvyAdyTFUpucP8XOKWMyrKammwPLMDfQZncmtg<br />
> >oh8<br />
> > NA-PFsRKaUxsRnrdbFId7a7dW2mkkOHqrr4TFgpalZC775KF1njtbF4p&sig=AHIEtbTLv5Xg<br />
> >Sx5 m0wfXO3sMV7vzJlgOtg&pli=1<br />
> ><br />
> > Hope it helps,<br />
> ><br />
> ><br />
> > 2011/4/13 jiayudai <daijiayu@nudt.edu.cn><br />
> ><br />
> > > Dear users,<br />
> > ><br />
> > > It is well known that GW method can give much more accurate band gap<br />
> > > since it considers many body interaction, and thus it can give more<br />
> > > accurate optical properties. What i am thinking is that what's the<br />
> > > difference between the optical properties from TDDFPT and GW. I mean,<br />
> > > TDDFPT has the same accuracy as the GW method? or what's the advantage<br />
> > > of TDDFPT over the GW except the computationl cost?<br />
> > ><br />
> > > Thanks a lot.<br />
> > ><br />
> > > Jiayu<br />
> > ><br />
> > ><br />
> > > -------------------------------------------<br />
> > > Jiayu Dai<br />
> > > Department of PhysicsNational University of Defense Technology,<br />
> > > Changsha, 410073, P R China<br />
> > > -----------------------------------------<br />