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]<mailto:[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]<mailto:[email protected]>> on behalf of Abhirup Patra <[email protected]<mailto:[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<http://www.max-centre.eu/quantum-espresso>) users mailing list [email protected]<mailto:[email protected]> https://lists.quantum-espresso.org/mailman/listinfo/users
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