[DFTB-Plus-User] total energies for isolated B , C and N

[Benjamin Hourahine]

Hello Khalfoun,

Isolated atom energies are not well defined in DFTB, they will depend on the Slater-Koster parameters that you are using.

You can simulate the isolated atom on its own to obtain an energy.But you should be aware that DFT (and derived theories) often cannot correctly obtain the electronic state of isolated atoms in standard theories (the triplet state of C  for example). Also the energy in DFTB will not contain some double counting contributions for isolated atoms (the repulsive term that provides this is strictly two centre), so relative energies to other structures can be evaluated but not absolute atomic energies.

Regards

Ben

On 21/12/2019 12:30, khalfoun hafid via DFTB-Plus-User wrote:
Dear DFTB+ Users,

What are the total energies of isolated B, C and N ?
How do we do for performing such energies ?

Thanks



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