Paolo, Thanks for the response. This gives me some more insight into what is going on, but I still don't understand.
As far as I can tell, the drhoscf in ef_shift is still the change in the density rather than the change in the potential, because the calls in solve_linter to dv_of_drho are using a copy of the density response rather than drhoscf itself: call zcopy (nrxx*nspin_mag,drhoscfh(1,1,ipert),1,dvscfout(1,1,ipert),1) call dv_of_drho (imode0+ipert, dvscfout(1,1,ipert), .true.) The heart of the matter is the lines in ef_shift: delta_n = delta_n + omega*drhoscf(nl(1),is,ipert) def (ipert) = - delta_n / dos_ef delta_n does not seem to refer to \Delta n_{ext} or the integral of the LDOS with \Delta V_{SCF}, as in the numerator of Eq. 79. Do those quantities exist in the calculation here? Thanks, David Strubbe UC Berkeley On Tue, Apr 19, 2011 at 1:44 PM, Paolo Giannozzi <giannozz at democritos.it>wrote: > > On Apr 8, 2011, at 20:39 , David Strubbe wrote: > > > Eq. 79 refers to a quantity \Delta n_{ext} and an integral of the LDOS > > with \Delta V_{SCF} to calculate the shift in Fermi level. However in > > ef_shift it appears that the density response drhoscf is used instead > > of these quantities in the numerator, which doesn't seem like the > > same thing. > > it doesn't, but it is. The (dirty) trick is well hidden in the call > to routine dv_of_drho: > it accepts in input the variation of the charge density, returns in > output the > variation of the potential, overwritten on the former. It was done a > looong time > ago in order to spare some memory, when machines had much less ram and > the code was much simpler and smaller (occasional dirty tricks were > under > control, sort of). A comment in the code would have spared you (and me) > some time. Unfortunately comments in code tend to belong to one of the > following categories: 1) useless, 2) misleading, 3) obsolete, 4) > nonexistent > > P. > --- > Paolo Giannozzi, Dept of Chemistry&Physics&Environment > Univ. Udine, via delle Scienze 208, 33100 Udine, Italy > Phone +39-0432-558216, fax +39-0432-558222 > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110419/996e9183/attachment.htm