Dear Mostafa Thanks for pointing out my mistake in the title of the email. Actually, I need to compute DeltaG, DeltaH and DeltaST for the reaction, TiO2 --> TiO2-1 + 1/2O2. for this, i need vibrational frequencies of TiO2 and TiO2-1. If relax the surfaces with DFT+U and then use simply DFT calculations for calculating frequencies, what would be the effect on frequencies?
On Wed, Aug 12, 2015 at 8:02 PM, Mostafa Youssef <[email protected]> wrote: > Hi Adnan, > > > The effect of DFT+U on the phonon dispersion of materials with soft-modes > such as TiO2 is large. Not only quantitatively but also qualitatively. See > for example: > > http://www.sciencedirect.com/science/article/pii/S1567173910004682 > > > and figure 8 in: > > http://iopscience.iop.org/0953-8984/26/12/122203/ > > > If your main goal is to study phonons of TiO2 , I would recommend LDA or > PBEsol. But if you insist on using DFT+U , then you can use PHONOPY + > PWscf code of Q.E equipped with a *large* supercell of TiO2. This should > allow you to calculate phonon dispersion in frozen phonon approximation > with Parlinski et al interpolation. Please follow the instructions on > PHONOPY website. > > > Mostafa YOussef > MIT > P.S. Somehow I read the title of your thread as DFT+U cartoons ! > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > -- Best Regards Muhammad Adnan Saqlain
_______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
