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 > >
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