[CP2K:10514] Huge difference in adsorption energies between CP2K and VASP with PBE

[hut... at chem.uzh.ch]

Hi

you are using a DZVP basis, this is rather small. Check the number
of basis functions. Do the same for the FHIaims calculation
and compare.
The cutoff of VASP cannot be compared to a local basis set.

regards

Juerg Hutter 
--------------------------------------------------------------
Juerg Hutter                         Phone : ++41 44 635 4491
Institut für Chemie C                FAX   : ++41 44 635 6838
Universität Zürich                   E-mail: hut... at chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

-----cp... at googlegroups.com wrote: -----
To: "cp2k" <cp... at googlegroups.com>
From: "Sharma SRK Chaitanya Yamijala" 
Sent by: cp... at googlegroups.com
Date: 07/12/2018 07:55PM
Subject: Re: [CP2K:10514] Huge difference in adsorption energies between CP2K and VASP with PBE

Dear Prof. Hutter,

Thanks. I will try the BSSE correction with CP2K. Regarding k-point sampling, in both the softwares, I have used Gamma point only. Could you please elobarate your point on "size of basis sets" here? I don't know how should I compare VASP basis (plane waves) with CP2K (both PW and Gaussians)? I have converged the CUTOFFs in both the cases such that the energy differences are < 1 meV. 

Also, yesterday, I have performed similar calculations with FHIAims and I have obtained the adsorption energy (withOUT dispersion and BSSE corrections) as 0.412 eV which is again closer to the VASP result and to the result in the reference.

Seeking your advice.

Thanks,
Sincerely,
Sharma.

On Thursday, July 12, 2018 at 12:11:59 AM UTC-7, jgh wrote:Hi 
 
my first guess: you didn't calculate the BSSE correction. 
 
other possible contributions: size of basis sets 
                              k-point sampling 
 
regards 
 
Juerg Hutter 
-------------------------------------------------------------- 
Juerg Hutter                         Phone : ++41 44 635 4491 
Institut für Chemie C                FAX   : ++41 44 635 6838 
Universität Zürich                   E-mail: hut... at chem.uzh.ch 
Winterthurerstrasse 190 
CH-8057 Zürich, Switzerland 
--------------------------------------------------------------- 
 
-----cp... at googlegroups.com wrote: ----- 
To: cp... at googlegroups.com 
From: "Sharma SRK Chaitanya Yamijala"  
Sent by: cp... at googlegroups.com 
Date: 07/12/2018 01:48AM 
Subject: [CP2K:10507] Huge difference in adsorption energies between CP2K and VASP with PBE 
 
Dear CP2K members, 
 
I am calculating the adsorption energies of CO on ZnO (4x4-slab with 4 layers of ZnO(10-10) surface). The adsorption energy obtained from VASP is ~ 0.3 eV (without dispersion) and it is ~ 0.45 eV (with dispSECTION_PARAMETERS TRUEersion). However, when calculating the same system with CP2K (geometry is re-optimized), I am obtaining the energies 0.688 eV and 0.863 eV for without and with dispersion correction, respectively.  
 
The literature value is close to the VASP result. Here is the reference (kindly, see Table 2, C-down, 2x1 cell, Full). 
 
B Meyer and D Marx 2003 J. Phys.: Condens. Matter 15 L89 
http://iopscience.iop.org/article/10.1088/0953-8984/15/2/112/pdf 
 
Could anyone give an advice on why there is such a discrepancy in the adsorption energies irrespective of using the same functional?  
 
I am attaching the geometry and the input file for your reference. 
 
Thanks, 
Sharma. 
 
-------------------------------------------------------------------- 
SRK Chaitanya Sharma, Yamijala. 
http://www.bmwong-group.com/group-members/ 
 
    
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[attachment "1CO_on_opt_4x4_slab.xyz" removed by Jürg Hutter/at/UZH] 
[attachment "zno_bulk.inp" removed by Jürg Hutter/at/UZH] 
  
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