[gpaw-users] Benzene optimization 'Did not converge'

[qian li]

Dear Sir or Madam,

I am the new user of GPAW.
When I optimize the benzene with h=0.20, it is converged. But when I change
h from 0.2 to 0.18, it can't  be converged even though I use basis dzp for
optimization.
Does h have some special sensitivity to the box? Should  some other
parameters be added in the file to make it converged?
Thank you very much for your warmhearted help!

This is the input file.

from ase import *

from gpaw import *

from gpaw.transport.tools import sort_atoms

from ase.io import read,write

from ase.visualize import view

from ase.lattice.surface import *

from ase.optimize import QuasiNewton

from ase.data.molecules import molecule

import numpy as np

atoms = read('benzene_gas.xyz')

atoms.set_cell([20,20,22])        # Set unit-cell (cubic 10x10x10≈)

atoms.center()                    # Center atoms in unit-cell

# Define GPAW calculator

vdw = 'vdW-DF'

calc = GPAW(xc=vdw,# XC functional

            h=0.18,

            basis='dzp',

            txt="optimize_gas.txt")  # Output text file


atoms.set_calculator(calc)        # Attach calculator to atoms


relax = QuasiNewton(atoms,                    # Attach minimizer to atoms

                    trajectory='optimize_gas.traj', # Trajectory file

                    logfile='qn.log')         # Optimizer output


relax.run(fmax=0.05)               # Run optimization, max force 0.05 eV/≈


calc.write("optimize_gas.gpw")     # Write GPAW output (density, etc...)


This is the error:


GPAW CLEANUP (node 5): gpaw.KohnShamConvergenceError occurred.  Calling
MPI_Abort!

  File "benze.py", line 27, in ?

    relax.run(fmax=0.05)               # Run optimization, max force 0.05
eV/≈

  File "/kemi/strange/ase/ase/optimize/optimize.py", line 114, in run

    f = self.atoms.get_forces()

  File "/kemi/strange/ase/ase/atoms.py", line 650, in get_forces

    forces = self._calc.get_forces(self)

  File "/users/kemi/strange/gpaw/gpaw/aseinterface.py", line 69, in
get_forces

    force_call_to_set_positions=force_call_to_set_positions)

  File "/users/kemi/strange/gpaw/gpaw/paw.py", line 283, in calculate

    raise KohnShamConvergenceError('Did not converge!')

gpaw.KohnShamConvergenceError: Did not converge!


Best regards

Qian Li

university of copenhagen
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