Dear Gabriele,
> Things that I have tried (with no joy, and, I must admit, without knowing > very well what I was doing): That's the main problem! You should start exactly from this point. You need to understand every step you do, otherwise what is the point? I would recommend to go through the tutorial about TDDFPT: http://indico.ictp.it/event/7921/session/325/contribution/1280/material/0/0.pdf What is your input for PW calculation? In the links that you provided there is no one pointing to the PW input. But from the PW output it seems that you are using the VdW correction - do you really need it? For an isolated molecule there is no need in the VdW correction. So maybe it would be useful also to go through tutorials on basic PW calculations: http://indico.ictp.it/event/7921/other-view?view=ictptimetable http://qe2019.ijs.si/program.html Greetings, 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 [email protected] <[email protected]> Sent: Friday, June 26, 2020 4:04:26 PM To: [email protected] Subject: [QE-users] help with turbo-davidson not converging hello I'm having convergence problems with a turbo-davidson calculation on an isolated (neutral) molecule of a Ru complex: http://www.dscf.units.it/~balducci/tmp/turbo-davidson-problem/XEDFAQ_1.png I have limited experience with this kind of calcs, but some time ago I did similar calcs on another molecule of the same type without any apparent problem (see also below). So far my protocol is: => geometry relaxation of the isolated molecule (cubic cell (a=21.50 ang) with a minimum inter-image distance of 10.1 ang, gamma point) => scf calculation with nbnd=120 (there are 96 occupied bands) http://www.dscf.units.it/~balducci/tmp/turbo-davidson-problem/scf.in.txt => turbo-davidson run: http://www.dscf.units.it/~balducci/tmp/turbo-davidson-problem/davidson.in.txt ----8<---- &lr_input outdir='./tmp', restart=.false. / &lr_dav p_nbnd_occ=10 p_nbnd_virt=10 num_init=60 num_eign=25 num_basis_max=200 residue_conv_thr=1.0E-4 start=0.18866813 ! 483 nm finish=0.23792873 ! 383 nm step=0.001 reference=0.21021155 ! 433.5 nm broadening=0.005 poor_of_ram=.true. poor_of_ram2=.true. lplot_drho=.true. / ----8<---- As said, the turbo-davidson calculation doesn't seem to be going anywhere; here is a typical pattern of the "Largest residue" figure vs n. of iterations: http://www.dscf.units.it/~balducci/tmp/turbo-davidson-problem/convergence.png and here is an output: http://www.dsch.univ.trieste.it/~balducci/tmp/turbo-davidson-problem/davidson.out.txt Things that I have tried (with no joy, and, I must admit, without knowing very well what I was doing): => increase num_init => decrease num_eign => decrease the energy range (start,finish) => increase num_basis_max => switch vdW-DF off in the scf run => increase p_nbnd_occ and p_nbnd_virt The only way I could get a converged result so far has been to request a single eigenvalue (num_eign=1): however, I guess this is simply extreme tweaking of the calculation: even in this conditions, it took some 22 iterations to converge, which seems too much to me. I have tried to reproduce my previous calc (the one which worked smoothly) since qe version at the time was different (I'm presently using qe-6.5); the molecule was this (ionic species, charge +2): http://www.dscf.units.it/~balducci/tmp/turbo-davidson-problem/fbt1805_1.png With the following input: ----8<---- &lr_input outdir='./tmp', restart=.false. / &lr_dav p_nbnd_occ=10 p_nbnd_virt=10 num_init=60 num_eign=25 num_basis_max=200 residue_conv_thr=1.0E-4 start=0.15 finish=0.185 step=0.001 broadening=0.005 reference=0.1675 poor_of_ram=.true. poor_of_ram2=.true. lplot_drho=.true. / ---->8---- the calculation converges straightforwardly with qe-6.5: ----8<---- Largest residue: 0.051299398950 Largest residue: 0.014049254805 Largest residue: 0.005898374852 Largest residue: 0.002998212328 Largest residue: 0.003119825980 Largest residue: 0.001028311667 Largest residue: 0.000741910032 Largest residue: 0.000399386757 Largest residue: 0.000545167736 Largest residue: 0.000146498010 Largest residue: 0.000098106072 ---->8---- I'm out of ideas and hoping that someone on the list can give me a clue (apologies: I realize that the statement of the problem is rather vague, but I don't know how to be more precise than this) Needless to say, I will be happy to provide any further information which might be useful thanks a lot in advance for any hint/suggestion ciao -gabriele -- Gabriele Balducci - Dipartimento di Scienze Chimiche e Farmaceutiche - Via L. Giorgieri 1 I-34127 TRIESTE tel: I-040-5583957 fax: I-040-5583903 e-mail: [email protected] Please, if possible, don't send me MS Word or PowerPoint attachments Why? See: http://www.gnu.org/philosophy/no-word-attachments.html _______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
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