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**Questions and Answers / Re: General question about total energy in ATK**

« **on:**March 23, 2021, 18:26 »

The total energy is basically the expectation value of the many-body DFT Hamiltonian. As such the sign matters: the lower the energy the more stable the configuration. Remember that adding an arbitrary constant scalar potential to the Hamiltonian does not change the physics (wave functions and density will be the same) but shifts the total energy. This mean that the actual value of the total energy is not of much use, only energy differences. In you example the important property is the difference in energy between two configurations ΔE = E

Note that the total energy is dependent on the pseudopotentials. So be sure that when you calculate energy differences between two configurations they should use the same pseudopotentials (you should in general try to use the same computational settings for the two calculations).

_{B}- E_{A}. If ΔE is negative it means that configuration B is more stable than configuration A.Note that the total energy is dependent on the pseudopotentials. So be sure that when you calculate energy differences between two configurations they should use the same pseudopotentials (you should in general try to use the same computational settings for the two calculations).