Dear Farah, first of all: total energies are always defined up to a constant. if anything, you should be looking at energy differences (e.g. between different crystal structures or magnetic orderings if that applies to your case) rather than total energies per se. Also, your expectation is not right: the DFT+U total energy (as usually written) is not variational with respect to U. That is why (or one of the reasons why) typically you need linear-response calculations to compute it (PRB 71, 035105) rather than a trivial minimization of the energy.
Best regards, Matteo On Thu, Jun 8, 2017 at 9:34 AM, FARAH MARSUSI <[email protected]> wrote: > Dear all, > > I have done DFT+U calculations in a semi-empirical way by increasing U > parameter until the magnetic moment (M) equal to experimental value was > obtained along with a phase transition from metal to insulator, as seen in > experiment. All physical findings are reasonable, except total energies. By > increasing U and reaching to experimental M, total energy is increasing > too. I expected the lowest total energy for it! > > > Best regards, > > F. Marsusi, > > Department of Physics, > Amirkabir University of Technology. > > -- > This email was Anti Virus checked by Security Gateway. > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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