The ABINIT Users Mailing List ( CLOSED )

["LEE Chin Chai" <cc-lee@imre.a-star.edu.sg>]

Dear all ABINIT users,

 

Currently, I am trying out to test out a few pseudopotential files (GGA.fhi format) for Co, Si, O and Ni before doing some supercell relaxation. But I have some problems in calculating their respective cohesive energy. I started on Si first as there is a tutorial that guides me (new user) along to use abinit. In order to calculate the cohesive energy for Si, I would have to calculate ground state energy of a Si atom. Can some one please guide me on how to set the parameter for the input file for the calculation of ground state energy of an atom? Is it a must to state their occupancy in order to obtain the correct the ground state energy? If so, please give me some points on how state the occupancy for different elements. Is it possible to do such calculation by setting nsppol to 2 only?

 

I am using Abinit version 4.6.5. When I tried using nsppol to 2, the ground state energy for Si is about -3.738 Hartree while the total energy for the 2 atoms primitive unit cell for Si is about -7.8761Hatree. So the cohesive energy (E_coh = E_tot – 2*E_Si_atom) that I obtained is about 0.4001 Hartree and it is far too big. If I am not wrong, the ground state energy that I have calculated is wrong. But where have I gone wrong, please kindly advise. Thank you.

 

Cheers,

ChinChai

 

 

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