Dear Willem and others, As far as I could infer from the guide alone, that seems to be true. However, I don't understand from the documentation how the A tag is then used if the CELL_PARAMETERS section is provided. From the examples I have tried out, the A tag seems to be simply incompatible with CELL_PARAMETERS as the error persists.
Any references or documentation on what the A tag actually does would be more than welcome as I cannot infer it from the official documentation Also: any obvious solution to scale the system (either scaling the lattice or even enforcing the volume) is very much appreciated. Editing the structural input parameters is somewhat tedious if this has to be done many times for the same system (e.g. in order to collect E(V) data for an equation of state). Thanks, Siebe ________________________________ From: users <[email protected]> on behalf of Offermans Willem <[email protected]> Sent: 08 October 2019 17:24 To: Quantum ESPRESSO users Forum <[email protected]> Subject: Re: [QE-users] Scaling factor for Dear Siebe and Quantum Espresso friends, According to me, the tag A in &SYSTEM has a different meaning. See: https://www.quantum-espresso.org/Doc/INPUT_PW.html#idm231 Met vriendelijke groeten, Mit freundlichen Grüßen, With kind regards, Willem Offermans Researcher Electrocatalysis SCT VITO NV | Boeretang 200 | 2400 Mol Phone:+32(0)14335263 Mobile:+32(0)492182073 [email protected]<mailto:[email protected]> [cid:[email protected]] On 8 Oct 2019, at 17:07, Siebe Vanlommel <[email protected]<mailto:[email protected]>> wrote: Hi all, I am trying to figure out whether there is a way to scale all three unit cell vectors at once in QE using pw.x. In my input file, I am using the CELL_PARAMETERS card (in units of Angstrom) to specify a unit cell. This (https://www.mail-archive.com/[email protected]/msg19387.html) old post seems to suggest that the 'A' parameter in the &SYSTEM section acts as a scaling parameter if 'ibrav==0' and the CELL_PARAMETERS card is used to specify the lattice. I take this to mean that each lattice vector is multiplied by *A, where A is a dimensionless number. However, QE complains that: "Error in routine cell_base_init (2): lattice parameter specified twice" I've tried specifying the atomic positions in 'crystal' (fractional) coordinates and in Angstroms but to no use. Input file is attached below. I'm using QE version 6.4.1. Is the interpretation of A as a scaling parameter with these settings deprecated, or am I missing something? Thanks in advance, Siebe input file: &CONTROL title = 'cha' , calculation = 'scf' , wf_collect = .true. , etot_conv_thr = 1.0D-6 , / &SYSTEM ibrav = 0, A = 1.2, nat = 108, ntyp = 2, ecutwfc = 100 , nosym = .true. , / &ELECTRONS scf_must_converge = .true. , / CELL_PARAMETERS angstrom 13.738516409 -0.000070574 0.000007978 -6.869319180 11.897869408 -0.000009602 0.000010055 -0.000007302 14.715552482 ATOMIC_SPECIES O 15.99940 O.pbe-rrkjus.UPF Si 28.08551 Si.pbe-rrkj.UPF ATOMIC_POSITIONS crystal O 0.901932010 0.098069851 0.126854702 O 0.098068745 0.901933544 0.873144107 O 0.901940529 0.803877937 0.126862649 O 0.098062465 0.196127742 0.873139246 (...) K_POINTS gamma _______________________________________________ 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 Indien u VITO Mol bezoekt, hou aub er dan rekening mee dat de hoofdingang voortaan enkel bereikbaar is vanuit de richting Dessel-Retie, niet vanuit richting Mol, zie vito.be/route.<http://www.vito.be/route> If you plan to visit VITO at Mol, then please note that the main entrance can only be reached coming from Dessel-Retie and no longer coming from Mol, see vito.be/en/contact/locations.<http://www.vito.be/en/contact/locations> VITO Disclaimer: http://www.vito.be/e-maildisclaimer
_______________________________________________ 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
