total energy versus energy density

Total energy, geometry optimization, DFT+U, spin....

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woates
Posts: 6
Joined: Sun Feb 17, 2013 11:11 pm

total energy versus energy density

Post by woates » Thu Aug 01, 2013 3:23 am

I've been running several simulations on barium titanate and comparing energy for different atomic coordinate positions near equilibrium. The equilbrium lattice constants look reasonable as well as the qualitative trend of the energy as the atomic coordinates change. BUT, I find that the total energy is exactly the same if I use one or two unit cells given the same lattice spacing and doubled acell size. Since the units of energy are Hartree (instead of Hartree/volume), I don't understand why the total energy is independent of the number of unit cells.

Does anyone know if and how Abinit normalizes the energy?

Thanks,
Billy

spin1/2
Posts: 4
Joined: Tue Jan 25, 2011 6:15 am
Location: Rice University, USA

Re: total energy versus energy density

Post by spin1/2 » Sun Aug 04, 2013 8:23 am

Could you please attach your input files, and tell me the pseudopotentials you are using.
I may understand your problem better if I could run the files & see the outputs.

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