[QE-users] H2 molecule moves away from surface during relaxation

[Omer Mutasim]

I have tried 1.5 A also, but it still moves away by more than 3 A.Do you mean H2 molecule will dissociate , so i have to study two H atoms adsorption instead of H2 molecule? Why should i pull one H ? What is the significance of local maxima of E ,,? Can you please elaborate 
 i want to study the perpendicular & parallel adsorption. Does that mean molecular H2 adsorption can’t tale place over Ni5P4 ? Regards 


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On Monday, August 31, 2020, 2:18 PM, Tamas Karpati <tkarpati at gmail.com> wrote:

Hi,
H2 was probably too close to the surface atoms. Try starting from ca.
1.5 A  which is closer to the both M-H bond lengths.
It is probable that H2 will decompose without a barrier (ie. TS) in
which case i recommend optimize the probable
product (eg. Ni-H and P-H or what you see fit) then start pulling one
H from the M (=either Ni or P) gradually and
check what the other H does and whether or not you have a local
maximum (ie a TS) on the E profile.
HTH,
  t

On Sun, Aug 30, 2020 at 9:28 PM Omer Mutasim <omermutasim at ymail.com> wrote:
>
> Dear All
> I’m studying perpendicular  adsorption of H2 molecule,  After relaxing H2 molecule + Ni5P4 slab , i found that H2 molecule moved away from the surface by 3 Angstrom, initially it was 1 A far from surface
> Any explanation for this ?
>
>
> Sent from Yahoo Mail for iPhone
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