Dear all,
I'm running a calculation for phthalocyanines on Al surface. On top of
the standard PBE calculation (that exposed no difficulty), I would like
to run a SCF with PBE0.
For the molecule in the gas phase, the PBE0-SCF also went smoothly and I
recover literature results for the energy levels.
However, for the molecule adsorbed on 5 layers of Al(001), the SCF loop
(phi-psi) is not converging. At least, "dexx" fluctuates around 0.002Ry
for more than 10 iterations. In another run with 3 layers, no progress
is made after 30 iterations, and sometimes (say 1/10) also the phi-scf
loop is not converging after several iterations.
I switched to NCPP for the EXX calculation and kept the "m-p" smearing
as used for the surface, with nqx=1 for EXX. Part of the input is below,
full I/O can be retrieved at:
https://drive.google.com/drive/folders/1yTYWGrfWFUTcSkl_pXYzbOVYT9dsrXim?usp=sharing
To be noticed that the molecule (here, AlPh) may be spin-polarized (one
electron in a pi orbital, in the gas phase) or not depending on the
interaction with the substrate... Here I'm looking first to a
spin-compensated case.
Thank you for your help,
Guido
&CONTROL
calculation = 'scf' ...
/
&SYSTEM
ibrav = 6
a=14.2751509299088549285
c=22.0
nat = 182
ntyp = 4
ecutwfc = 70
ecutrho = 280
occupations = "smearing",
smearing = "m-p",
degauss = 0.02D0,
vdw_corr='grimme-d3'
input_dft='PBE0'
nqx1=1, nqx2=1, nqx3=1
/
&ELECTRONS
conv_thr = 1.0d-7
mixing_mode = "local-TF"
mixing_beta = 0.7
/
ATOMIC_SPECIES
C 12.0 C.0.0.UPF
H 1.0 H.nc2.UPF
N 14.0 N.nc2.0.0.UPF
Al 26 Al.vbc.UPF
ATOMIC_POSITIONS {angstrom}
--
Guido Fratesi
Dipartimento di Fisica
Universita` degli Studi di Milano
Via Celoria 16, 20133 Milano, Italy
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