Dear Giuseppe, 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.
Thanks. Jiayu From: Giuseppe Mattioli <[email protected]> Subject: Re: [Pw_forum] Spectra from GW and TDDFPT To: PWSCF Forum <pw_forum at pwscf.org> Message-ID: <201104131649.52909.giuseppe.mattioli at mlib.ism.cnr.it> Content-Type: text/plain; charset="utf-8" Dear Jiayu Yes, it is. With only one additional warning: the TDDFPT code works only at Gamma (and fixed occupations). It is not designed to deal with periodic systems where you need k-points, but (in my experience) it works well with molecules. On Wednesday 13 April 2011 15:20:59 jiayudai wrote: > 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/TDDF > >T2 > > 006/2006tddft/docs/school/Godby.pdf+TDDFT+and+GW&hl=en&pid=bl&srcid=ADGEE > >Siq > > 9Au0dGZsFvyPUtLL9nEaPg44xzN8NzkJiiguvyAdyTFUpucP8XOKWMyrKammwPLMDfQZncmtg > >oh8 > > NA-PFsRKaUxsRnrdbFId7a7dW2mkkOHqrr4TFgpalZC775KF1njtbF4p&sig=AHIEtbTLv5Xg > >Sx5 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 > > > ----------------------------------------- -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110414/63a7f365/attachment.htm
