mBJ should be used only for bulk solids (no vacuum). If there is vacuum, then the calculation of the average of (grad rho)/rho in the unit cell [see Eq. (3) in PRL, 102, 226401 (2009)] does not make any sense. A solution would be to fix the value of c [Eq. (3)], but this requires the modification of the subroutine vxclm2.f.
In case you want PBE-GGA total energy instead of LDA, you have to replace exu=2.d0*(exupls + eclsd) exd=2.d0*(exdnls + eclsd) by exu=2.d0*(exuppb + ecpbe) exd=2.d0*(exdnpb + ecpbe) in vxclm2.f (below IGRAD .EQ. 28). On Sun, 8 May 2011, Matthew Stream wrote: > Dear Prof. Tran: > thank you for your prompt reply. > > > What is not possible, is to use forces for > > the optimization of internal parameters. > > I got it. > > > What do you mean by QW, QWR, QD? > QW :Quantum Well, > QWR:Quantum Wire, and > QD :Quantum Dot, > respectively. > Is the similar procedure you suggested applicable to these structures, > if I use super cells appropriately for them? > > Thank you in advance. > > Mat > > -------- Original Message -------- > Subject: Re: [Wien] volume optimization > From: tran at theochem.tuwien.ac.at > To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at> > Date: 2011/05/08 16:28 > > > Hello, > > > > When you use mBJ (number 28 in case.in0), the total energy is calculated > > with LDA (i.e., the mBJ orbitals and electron density are plugged into > > the LDA functional), and you can use this total energy for calculation of > > energy vs. volume of unit cell. What is not possible, is to use forces for > > the optimization of internal parameters. What do you mean by QW, QWR, QD? > > > > Hybrid functionals similar to HSE are in WIEN2k, but I don't know when it > > will be released into the distributed WIEN2k version: > > http://arxiv.org/abs/1103.4466 > > > > F. Tran > > > > On Sun, 8 May 2011, Matthew Stream wrote: > > > > > Dear WIEN2k users and Prof. Blaha: > > > > > > Could you teach me if there's a way to calculate the Energy vs. volume > > > curve for bulk, QW, QWR, QD (whatever, e.g. GaAs bulk crystal) with > > > realistic band gap ( comparable to the experimental value)? > > > > > > As far as I know, mBJ is only a potential which is not applicable to the > > > optimization, while HSE functional is not yet introduced into WIEN2k. > > > > > > Kind regards, > > > Mat > > > _______________________________________________ > > > Wien mailing list > > > Wien at zeus.theochem.tuwien.ac.at > > > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > > > > > _______________________________________________ > > Wien mailing list > > Wien at zeus.theochem.tuwien.ac.at > > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > > > > _______________________________________________ > Wien mailing list > Wien at zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > >