[QE-users] how to study adsorption energy

[劉芸瑄]

Dear all
  I am a beginner in QE. Here are my question about adsorption energy. ( ex
H2O adsorb on Cu surface )

  I know that I have to optimize the structure of the adsorbent molecule
and the surface respectively. And then optimize the adsorbent + surface
system.

Getting the adsorption energy by the equation

Eads= E(Ad+surface)-[(Ead)+(Esurface)]


  But I am confused about the more specific step of how to use QE to study
it.

First , I think I have to build the surface with the molecule above it. I
try to use the BURAI to build the slab but I fail to build the molecule
above it. Because I can not built the molecule with accurate bond length or
angle which just like the Gaussview can do .

  Alternatively, I hope to use VESTA to build the slab and then output the
xyz file to Avogadro. And then build the more accurate molecule structure
above the slab by Avogadro. After that, output the xyz file to BURAI to
create the QE input file. Is that alright ? Or is there any software or
method that is more easily to build the molecule + slab surface system ?

  Also, which part or parameter that I should be aware of ? I think there
are still a lot to be concerned. Like the size of the slab, the distance
between adsorbent and surface , the QE input file parameter, all of these
could affect the convergence of the SCF and the accuracy of the energy. As
a beginner, how to start studying the adsorption energy ?

  I will really appreciate that if you could kindly teach me the more
specific instruction of adsorption energy calculation.

Thank you so much!


Best regards

Sydney Liu
-- 
TOK TAIWAN CO.,LTD
Sydney Liu
E-mail : danosunny at gmail.com
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