Dear Iurii, Thanks for the email. Sorry about not explaining it well. Here is what I meant: With spin-polarization and with gamma only kmesh none of the TDDFT code works (i.e. turbo_davidson, turbo_eels, turbo_lanczos). So it is difficult to simulate optical spectra for a "neutral (tot_charge = 0)" doped/defected structure. By "works", I meant that I could run the regular scf-calculation and TDDFT codes for any "non-zero (tot_charge = -1 or +1)" charged structure using "gamma only" kmesh and "non spin-polarization".
Please let me know if it's still confusing. Best, Abhirup ------------------------------------------------------------------------------------------------------------------------------------- Abhirup Patra Postdoctoral Research Fellow Department of Chemistry University of Pennsylvania On Thu, Dec 19, 2019 at 4:06 AM Timrov Iurii <[email protected]> wrote: > Dear Abhirup, > > > Sorry, I miss the point. Could you clarify please what do you mean by > saying "it works"? Do you refer to the k-points implementation of the > turbo_davidson code or something else? The k-points algorithm must be > disabled for all cases (neutral and charged cases), and if this not the > case, then I will modify the code in order to disable it. > > > Best, > > Iurii > > > -- > Dr. Iurii Timrov > Postdoctoral Researcher > STI - IMX - THEOS and NCCR - MARVEL > Swiss Federal Institute of Technology Lausanne (EPFL) > CH-1015 Lausanne, Switzerland > +41 21 69 34 881 > http://people.epfl.ch/265334 > ------------------------------ > *From:* users <[email protected]> on behalf of > Abhirup Patra <[email protected]> > *Sent:* Wednesday, December 18, 2019 9:36:51 PM > *To:* Quantum ESPRESSO users Forum > *Subject:* Re: [QE-users] k-point algorithm is not tested yet turbo > davidson > > Forgot to mention, it only happens if I do not assign any charge to the > structure i.e., for neutral case. However, it works for nonzero tot_charge, > spin-unpolarized situation with fixed smearing and turb_davidson works fine. > > Thanks for your comments. > > Best, > Abhirup > > ------------------------------------------------------------------------------------------------------------------------------------- > Abhirup Patra > Postdoctoral Research Fellow > Department of Chemistry > University of Pennsylvania > > > On Wed, Dec 18, 2019 at 3:29 PM Abhirup Patra <[email protected]> > wrote: > >> Thanks, Iurii. Yes, the spectrum with gamma point is quite reasonable but >> do not match with the experimental observation. It could be some other >> issue. >> >> However, I am wondering how to do the TDDFT calculation for a >> doped/defected structure with extra electron or hole. I tried to use >> turbo_davidson starting from i) scf calculation with npsin= 2 and total >> magnetization and turbo_davidson does not work since I believe it does not >> for spin-polarized system, then, I tried ii) scf calculation without any >> spin-polarization and the scf calculation did not run since it cannot work >> with an extra charge and 'fixed' occupation, and, finally, iii) scf with >> smearing but turbo_davidson does not support scf calculation with smearing >> (ref: >> https://lists.quantum-espresso.org/pipermail/users/2017-January/037363.html) >> >> >> I believe in this case I cannot use TDDFT of QE to calculate absorption >> spectra of a defected or doped structure. Am I right here? >> >> Best, >> Abhirup >> >> >> >> ------------------------------------------------------------------------------------------------------------------------------------- >> Abhirup Patra >> Postdoctoral Research Fellow >> Department of Chemistry >> University of Pennsylvania >> >> >> On Wed, Dec 18, 2019 at 4:00 AM Timrov Iurii <[email protected]> >> wrote: >> >>> Dear Abhirup, >>> >>> >>> > However, I am not sure with the number of atoms (~120 or more) GW-BSE >>> calculations with supercell is actually feasible. >>> >>> >>> Yes, I understand the issue. I do not know if it is feasible. You may >>> try to use e.g. Yambo and see how it goes. Otherwise, since you have >>> already quite a big cell, maybe with k=0 you obtain quite a reasonably >>> converged spectrum (to be checked w.r.t. the cell size) at the TDDFT level >>> in the adiabatic approximation. >>> >>> >>> Regards, >>> >>> Iurii >>> >>> >>> -- >>> Dr. Iurii Timrov >>> Postdoctoral Researcher >>> STI - IMX - THEOS and NCCR - MARVEL >>> Swiss Federal Institute of Technology Lausanne (EPFL) >>> CH-1015 Lausanne, Switzerland >>> +41 21 69 34 881 >>> http://people.epfl.ch/265334 >>> ------------------------------ >>> *From:* users <[email protected]> on behalf of >>> Abhirup Patra <[email protected]> >>> *Sent:* Tuesday, December 17, 2019 4:47:01 PM >>> *To:* Quantum ESPRESSO users Forum >>> *Subject:* Re: [QE-users] k-point algorithm is not tested yet turbo >>> davidson >>> >>> Thanks very much, Iurii. I really appreciate your answer and it does >>> make sense to me. With gamma point only it works fine. And, you are right, >>> my system is a solid and I am >>> trying to simulate the optical spectrum. However, I am not sure with the >>> number of atoms (~120 or more) GW-BSE calculations with supercell is >>> actually feasible. >>> >>> Best, >>> Abhirup >>> >>> ------------------------------------------------------------------------------------------------------------------------------------- >>> Abhirup Patra >>> Postdoctoral Research Fellow >>> Department of Chemistry >>> University of Pennsylvania >>> >>> >>> On Tue, Dec 17, 2019 at 7:50 AM Timrov Iurii <[email protected]> >>> wrote: >>> >>>> Dear Abhirup, >>>> >>>> >>>> As you can see from the error message of the turbo_davidson code, the >>>> k-points algorithm is not supported. Only Gamma point sampling can be used. >>>> >>>> >>>> If I understand correctly, your system is a solid, right? And you want >>>> to use a unit cell with a k-points mesh, right? The turbo_davidson cannot >>>> be used in this case. You may try to use a supercell with a Gamma point >>>> sampling. But be careful when using TDDFT in the adiabatic approximation >>>> for the absorption spectroscopy of solids. I recommend that you check >>>> literature on this topic. Maybe you will need to resort to the BSE >>>> approach. >>>> >>>> >>>> HTH >>>> >>>> >>>> Iurii Timrov >>>> >>>> >>>> -- >>>> Dr. Iurii Timrov >>>> Postdoctoral Researcher >>>> STI - IMX - THEOS and NCCR - MARVEL >>>> Swiss Federal Institute of Technology Lausanne (EPFL) >>>> CH-1015 Lausanne, Switzerland >>>> +41 21 69 34 881 >>>> http://people.epfl.ch/265334 >>>> ------------------------------ >>>> *From:* users <[email protected]> on behalf of >>>> Abhirup Patra <[email protected]> >>>> *Sent:* Monday, December 16, 2019 6:12:08 PM >>>> *To:* Quantum ESPRESSO users Forum >>>> *Subject:* [QE-users] k-point algorithm is not tested yet turbo >>>> davidson >>>> >>>> Hello, >>>> >>>> I am trying to use turbo_davidson starting from a SCF calculation using >>>> PBE without smearing and spin-polarization. This system is a non-metal with >>>> bandgap of 2.6 eV. I gave uniform k-mesh as follows for the bcc structure >>>> with lattice constant of 10.34 angstrom. >>>> >>>> K_POINTS {crystal_b} >>>> 9 >>>> 0.0 0.0 0.0 0 >>>> 0.0 -0.5 0.0 0 >>>> 0.0 -0.5 0.5 0 >>>> 0.5 -0.5 0.5 0 >>>> 0.5 -0.5 0.0 0 >>>> 0.5 0.0 0.0 0 >>>> 0.0 0.0 0.0 0 >>>> 0.0 0.0 0.5 0 >>>> 0.5 0.0 0.5 0 >>>> >>>> &lr_input >>>> prefix = 'pristine_pbe' >>>> outdir = './' >>>> ! wfcdir = './' >>>> / >>>> &lr_dav >>>> num_eign = 35, >>>> num_init = 70, >>>> num_basis_max = 200, >>>> start = 0.0d0 >>>> finish = 3.5d0 >>>> step = 0.001d0 >>>> broadening = 0.005d0 >>>> / >>>> >>>> However, I am getting the following error: >>>> >>>> Error in routine lr_readin (1): >>>> k-point algorithm is not tested yet >>>> >>>> I am wondering if there is a simple way out to this problem other than >>>> explicitly testing different k mesh combinations. >>>> >>>> Best, >>>> Abhirup >>>> >>>> ------------------------------------------------------------------------------------------------------------------------------------- >>>> Abhirup Patra >>>> Postdoctoral Research Fellow >>>> Department of Chemistry >>>> University of Pennsylvania >>>> _______________________________________________ >>>> Quantum ESPRESSO is supported by MaX ( >>>> www.max-centre.eu/quantum-espresso) >>>> users mailing list [email protected] >>>> https://lists.quantum-espresso.org/mailman/listinfo/users >>> >>> _______________________________________________ >>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso >>> ) >>> users mailing list [email protected] >>> https://lists.quantum-espresso.org/mailman/listinfo/users >> >> _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
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