[gpaw-users] beef error

Sat Feb 28 20:56:42 CET 2015

Regarding using the geometry converged with PBE or other xc.

I remember I had to do something similar for methanol. It simply wasn't converging with BEEF-vdW no matter what I tried.
What I did is I optimized the structure with PBE and used it as the start for the BEEF-vdW optimization (or maybe it was LCAO).
I did the same with LCAO for dimethylcarbonate and dimethyloxalate. It worked.

I would recommend doing this for  organic molecules and using it as a backup plan for molecules that aren't converging.
I'm not sure if I would do it always. Some molecules converge nicely.

Note: In the LCAO calculator I used basis = 'dzp'

Best regards,

Manuel
________________________________________
From: gpaw-users-bounces at listserv.fysik.dtu.dk [gpaw-users-bounces at listserv.fysik.dtu.dk] on behalf of Peter Bjerre Jensen [pbjen at dtu.dk]
Sent: Saturday, February 28, 2015 5:31 PM
To: gpaw-users at listserv.fysik.dtu.dk
Subject: Re: [gpaw-users] beef error

Hi Jess..

Den 28-02-2015 kl. 12:00 skrev gpaw-users-request at listserv.fysik.dtu.dk<mailto:gpaw-users-request at listserv.fysik.dtu.dk>:

Message: 1
Date: Sat, 28 Feb 2015 09:06:53 +0100
From: Jess Wellendorff <jess.wellendorff.dtu at gmail.com><mailto:jess.wellendorff.dtu at gmail.com>
To: gpaw-users at listserv.fysik.dtu.dk<mailto:gpaw-users at listserv.fysik.dtu.dk>
Subject: Re: [gpaw-users] beef error
Message-ID: <54F1771D.10804 at gmail.com><mailto:54F1771D.10804 at gmail.com>
Content-Type: text/plain; charset=windows-1252; format=flowed

One could also try to start from a converged GGA calculation, eg. PBE or
revPBE. This should give a fast and very good initial guess for the
BEEF-vdW electron density. Might even save time since the GGA SCF steps
are faster than the BEEF-vdW ones. It's very easy to switch to BEEF-vdW
after a converged GGA run:

h2o.calc.set(xc='BEEF-vdW')

Do you think one should do this generally to save computation time, and improve the success of convergence?

Best regards
Peter

Peter Bjerre Jensen
Postdoc
DTU Energy

Technical University of Denmark
        [cid:part1.09000908.08040102 at dtu.dk]

Department of Energy Conversion and Storage
Fysikvej, Building 307
2800 Kgs. Lyngby
Direct +45 45253204
pbjen at dtu.dk<mailto:pbjen at dtu.dk>
www.ecs.dtu.dk<http://www.ecs.dtu.dk>

- Jess

On 02/27/2015 11:23 AM, Manuel ?aric wrote:

Regarding H2O(g) with BEEF-vdW.

One should be able to do this:
"""
from ase import Atoms, Atom
from ase.optimize import QuasiNewton
from gpaw import GPAW, FermiDirac, Mixer
from ase.visualize import view
from gpaw.eigensolvers.davidson import Davidson
from ase.io import read, write

name = 'H2O'

cell = (12, 12, 12)
periodic = (0, 0, 0)

h2o = Atoms([Atom('O', position=(0, 0, 0)),
             Atom('H', position=(1, 0, 0)),
             Atom('H', position=(0, 1, 0))], cell=cell, pbc=periodic)
h2o.center()
view(h2o)

h = 0.18
nbands = -10
xc = 'BEEF-vdW'
mixer = Mixer(0.05, 5 , weight=50.0)
eigensolver = Davidson(niter=2)

calc = GPAW(h=h,
            xc=xc,
            mixer=mixer,
            eigensolver=eigensolver,
            nbands=nbands,
            txt='%s.txt' % name)

h2o.set_calculator(calc)

dyn = QuasiNewton(h2o, trajectory='%s.traj' % name,  logfile='%s.log' % name)
dyn.run(fmax=0.05)

calc.write('%s.gpw' % name)
"""
Should work for O2(g) as well.

I remember having problems when I tried using a larger cell with pbc = ((1, 1, 1))

Hope it helps
______________________________________
From: Marcin Dulak
Sent: Wednesday, February 25, 2015 1:02 PM
To: Logi Arnarson; gpaw-users at listserv.fysik.dtu.dk<mailto:gpaw-users at listserv.fysik.dtu.dk>; Manuel ?aric
Subject: RE: beef error

Hi,

the calculation scf does not converge.
I believe this is a common problem with the BEFF-vdw functional for molecules,
see http://listserv.fysik.dtu.dk/pipermail/gpaw-users/2014-May/002686.html
I would try to set width=0.1 eV and check you don't get fractional occupancies in the solution.
Manuel: how do you converge molecules with BEEF-vdw?

Best regards,

Marcin
________________________________
From: Logi Arnarson [logi at au.dk<mailto:logi at au.dk>]
Sent: Wednesday, February 25, 2015 9:24 AM
To: gpaw-users at listserv.fysik.dtu.dk<mailto:gpaw-users at listserv.fysik.dtu.dk>
Subject: beef error

Dear GPAW Users,

I am trying to estimate the error of a formation energy calculation using the the BEEF-vdw functional. The calculation is for a Vanadia Oxide species on a surface (VO3H/TiO2) where the VO3H is calculated with respect to V2O5(b) and H2O(g).
In the script (see script.txt) I therefore read the respective gpw files in order to get the potential energies. Then I get KohnShamConvergenceError for the H2O calculation (see error.txt). I have done analogous beef calculation for a VO3 species where instead of having H2O(g) as the reference but O2(g) which doesn't  give rise to an error. The calculations for H2O(g) and O2(g) are done in exactly the same way.

Is there someone out there who might know how to fix this?

Regards,
Logi

--
Logi Arnarson
PhD Student
iNANO, AArhus University

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