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