Dear all QE users,
I'm now calculating adsorption energy of a hydrogen molecule on cobalt
(0001) surface.
I referred some papers: Yu et al, Int J Hydrog Energy, 2018, and Helden et
al, ACS catalysis, 2012
They reported results of dissociative adsorption of H2 molecule to top site
about ~-0.2 eV, and fcc hollow site about ~-1 eV.
But in my calculation, I have some different results in both cases, -0.4 eV
and -1.2 eV.
Although I used different method and basis set (PBE, PAW), I think that the
difference about 0.2 eV for each case are quite large just considered as a
simple error from using different method and basis sets.
Other settings are almost same(kinetic energy cutoff, smearing,
spin-polarized, etc).
I did not include zero point energy correction, but it seems that ZPE
correction is not large for this case.
This is my input script (adsorbed state)
---------------------------------------------------------------------------------------
&CONTROL
title = 'Co_da'
calculation = "relax"
restart_mode = 'from_scratch',
tprnfor = .TRUE.,
prefix = 'Co_da'
max_seconds = 432000
pseudo_dir = './'
outdir = './work'
disk_io = 'low'
wf_collect = .TRUE.
/
&SYSTEM
a = 7.47797
b = 7.47797
c = 38.06076
cosab = 5.00000e-01
degauss = 1.46997e-02
ecutrho = 2.94E000+02
ecutwfc = 3.67493e+01
ibrav = 12
nat = 38
nspin = 2
ntyp = 2
occupations = "smearing"
nosym = .TRUE.
smearing = "methfessel-paxton"
starting_magnetization (1) = 2.00000e-1
starting_magnetization (2) = 2.00000e-1
/
&ELECTRONS
conv_thr = 1.00000e-06
electron_maxstep = 600
mixing_beta = 3.00000e-01
mixing_mode = "local-TF"
startingpot = "atomic"
startingwfc = "atomic+random"
/
&ions
/
&cell
/
K_POINTS {automatic}
6 6 1 0 0 0
ATOMIC_SPECIES
Co 58.93320 Co.pbe-n-kjpaw_psl.1.0.0.UPF
H 1.00794 H.pbe-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS {angstrom}
~~~~~
---------------------------------------------------------------------------------------
Can anyone recommend some advice for me to correct this error?
Thanks in advance.
Dongwoo Kang
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