[Pw_forum] Cannot reproduce standard CO/Au(111) adsorption energy

[Duy Le]

How did you evaluate energy of a CO molecule?
--------------------------------------------------
Duy Le
PhD Student
Department of Physics
University of Central Florida.

"Men don't need hand to do things"



On Tue, Jul 6, 2010 at 4:45 PM, Janesko, Benjamin <b.janesko at tcu.edu> wrote:
>> On Jun 25, 2010, at 19:34 , Janesko, Benjamin wrote:
>>
>> > Everything looks reasonable in XCrysDen
>>
>> and what is the C-Au or O-Au distance? it seems to me that the CO
>> molecule is very far away from the gold surface. If so, it is normal to
>> find very small binding energies
>>
>> P.
>> ---
>> Paolo Giannozzi, Dept of Physics, University of Udine
>
> I've rerun from a different starting geometry, and it only partially solved the problem. The optimum C-Au distance is now 2.24 Angstrom, and the new CO-Au(111) adsorption energy is -0.003978 Rydberg = -0.055 eV. Again, this is much smaller than the PBE CO/Au adsorption energy -0.26 eV from Quantum Espresso calculations reported in PRB 77, 085414 (2008). I've done some potential energy surface scans with rigid CO and Au groups, and haven't seen anything helpful. I've attached my CO/Au(111) input file below. Any further explanations of how my calculations differ from the above reference would be appreciated. Thanks again.
>
>  - BGJ
>
> &control
>    calculation='relax'
>    prefix='coau5-3x3-fcc3',
>    pseudo_dir = '/home/bjanesko2/espresso/pseudo//',
>    outdir='/tmp/espresso/'
>  /
>  &system
>    ibrav=4,
>    celldm(1)=9.439624066,
>    celldm(3)=8.0,
>    nat=17,
>    ntyp=3,
>    ecutwfc = 40.0,
>    ecutrho = 250.0,
>    occupations='smearing', smearing='marzari-vanderbilt', degauss=0.01
>  /
>  &electrons
>    conv_thr=0.0000001
>  /
>  &ions
>   ion_dynamics='bfgs',
>   path_thr=0.03
>  /
> ATOMIC_SPECIES
>  Au  196.966  Au.pbe-nd-van.UPF
>  C   12.0107  C-pbe-van_ak.UPF
>  O   15.9994  O-pbe-van_ak.UPF
> ATOMIC_POSITIONS alat
> Au      0.000000        0.000000        4.000000  1 1 1
> Au      0.500000        0.288675        4.000000  1 1 1
> Au      1.000000        0.577350        4.000000  1 1 1
> Au      0.333333        0.000000        3.528595  1 1 1
> Au      0.833333        0.288675        3.528595  1 1 1
> Au      1.333333        0.577350        3.528595  1 1 1
> Au      0.666667        0.000000        3.057191  0 0 0
> Au      1.166667        0.288675        3.057191  0 0 0
> Au      1.666667        0.577350        3.057191  0 0 0
> Au      1.000000        0.000000        2.585786  0 0 0
> Au      1.500000        0.288675        2.585786  0 0 0
> Au      2.000000        0.577350        2.585786  0 0 0
> Au      1.333333        0.000000        2.114382  0 0 0
> Au      1.833333        0.288675        2.114382  0 0 0
> Au      2.333333        0.577350        2.114382  0 0 0
> C        0.333333333   0.000000000   4.317809266452 1 1 1
> O        0.333333333   0.000000000   4.546726732327 1 1 1
> K_POINTS automatic
> 8 8 1 0 0 0
>
>
>
> ===================
> Benjamin G. Janesko
> Assistant Professor
> Department of Chemistry
> Texas Christian University
> Office: SWR 428
> http://personal.tcu.edu/bjanesko/
> b.janesko at tcu.edu
> Phone: 1-817-257-6202
> Fax: 1-817-257-5851 (attn:janesko)
> ******************
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