Dear Wien2k mailing list, I have two questions regarding the mBJ potential.
I'm working on some TiO2 based ternary oxide solid solutions. The supercells were relaxed using PBE and than I'm using the mBJ to calculate band gaps and optical properties. The known problem for TiO2 with PBE (but also with LDA and maybe even some hybrids) is that the anatase is predicted as the most stable structure instead of rutile. However I have noticed, that mBJ actually gets this right. So I was wondering if this would be a good enough reason to use the mBJ total energies in discussion of for example structural stability and similar stuff for the TiO2 based solid solutions instead of the PBE ones. I am aware that this has been brought up multiple times on the mailing list, however there seems to be some disagreement, with some post implying the mBJ total energies (and total energy dependent quantities) should not be used at all: http://www.mail-archive.com/wien%40zeus.theo chem.tuwien.ac.at/msg08020.html and some other posts suggest that maybe in some special cases it can be used: http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg08522. html http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg08523. html What would be your opinion in this case? Another question is regarding the mBJ-GGA. It has been mentioned several times, that it is possible to use GGA instead of LDA for energy functional in mBJ. So far I've always used the default mBJLDA and applied it to structures relaxed using the PBE (as recommended in the original mBJ article). However I have been asked, if it maybe would be better to use mBJ with PBE as energy functional, when I have structures relaxed with PBE? My current understanding is that since the mBJ parameters were calibrated using LDA as energy functional, to use it with some else I would need to recalibrate (refit) the parameters. Is this understanding correct? Best regards Pavel Ondračka _______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://firstname.lastname@example.org/index.html