Dear All,
I want to calculate the binding energy of a single metal atom on graphene. I did two runs using VASP; (1) Metal atom on graphene optimization, (2) Metal atom far away from graphene and optimization. I find the energy differences to be too large. What am I doing wrong? Your help would be much appreciated. Thanks. Regards.
Binding energies in VASP
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Re: Binding energies in VASP
Hi,
sometimes it's tricky to get the proper state of the atom. I'd suggest to check the DOS. It becomes a lot easier if you calculate the atom all alone. Destroying the symmetry (i.e., don't use a cubic box here) also helps. As well as small smearing. You need(!) to hit the proper state of the single atom.
Cheers,
alex
sometimes it's tricky to get the proper state of the atom. I'd suggest to check the DOS. It becomes a lot easier if you calculate the atom all alone. Destroying the symmetry (i.e., don't use a cubic box here) also helps. As well as small smearing. You need(!) to hit the proper state of the single atom.
Cheers,
alex
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Re: Binding energies in VASP
@madhu
did you resolve the issue?
i think the binding energy (the way i do generally) is to be calculated like below
Step1 : create a system having material A + Material B separated at a distance closer enough to have bonding ----> Relax the system A.B
Step2: Run a static run using CONTCAR from Step1. This Energy A.B
Step3 : consider the CONTCAR obtained from Step1. Then create two separate POSCAR files of A and B, without changing the atoms positions of A and B materials in the whole crystal lattice. Means you need to maintain same lattice dimensions as that of CONTCAR obtained in Step1.
Step4: Run static run for new POSCAR for A. This is Energy A
Step5: Run static run for new POSCAR for B. This is Energy B
Step6: Use formula for binding energy = Energy A.B - [Energy A + Energy B]
Note: In all the calculations one must keep a constant ENCUT value. And preferably EDIFF and EDIFFG also.
Anyone kindly comment if this procedure is wrong or may need modification?
Regards
did you resolve the issue?
i think the binding energy (the way i do generally) is to be calculated like below
Step1 : create a system having material A + Material B separated at a distance closer enough to have bonding ----> Relax the system A.B
Step2: Run a static run using CONTCAR from Step1. This Energy A.B
Step3 : consider the CONTCAR obtained from Step1. Then create two separate POSCAR files of A and B, without changing the atoms positions of A and B materials in the whole crystal lattice. Means you need to maintain same lattice dimensions as that of CONTCAR obtained in Step1.
Step4: Run static run for new POSCAR for A. This is Energy A
Step5: Run static run for new POSCAR for B. This is Energy B
Step6: Use formula for binding energy = Energy A.B - [Energy A + Energy B]
Note: In all the calculations one must keep a constant ENCUT value. And preferably EDIFF and EDIFFG also.
Anyone kindly comment if this procedure is wrong or may need modification?
Regards
Regards
SKM
SKM
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Re: Binding energies in VASP
Thank you for your suggestion.