[QE-users] Relaxation of CaCO3

[Hassan Ahmed Mohammed]

Hello all,
I'm trying to study the adsorption of different compounds on a calcite
slab. I have been trying to do geometry relaxation for the calcite using QE
and used burai to generate the input file. It worked for a long time but it
did not converge. I tried several times with changes such as using kpoints
instead of gamma, using other pseudopotentials but no luck.
I appreciate any suggestions or ideas that could lead to my mistake!
Here is my input file

&CONTROL
calculation = "relax"
forc_conv_thr = 1.00000e-03
max_seconds = 1.72800e+05
nstep = 100
pseudo_dir = "."
tprnfor = .TRUE.
tstress = .TRUE.
/
&SYSTEM
a = 3.30600e+01
b = 1.45800e+01
c = 4.87600e+01
degauss = 1.00000e-02
ecutrho = 2.25000e+02
ecutwfc = 2.50000e+01
ibrav = 8
nat = 480
ntyp = 3
occupations = "smearing"
smearing = "gaussian"
/
&ELECTRONS
conv_thr = 1.00000e-06
electron_maxstep = 200
mixing_beta = 7.00000e-01
startingpot = "atomic"
startingwfc = "atomic+random"
/
&IONS
ion_dynamics = "bfgs"
/
&CELL
/
K_POINTS {gamma}

ATOMIC_SPECIES
Ca 40.07800 Ca.pbe-nsp-van.UPF
C 12.01070 C.pbe-rrkjus.UPF
O 15.99940 O.pbe-rrkjus.UPF

ATOMIC_POSITIONS {angstrom}
Ca 25.034002 5.792000 9.889249
.

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