Dear Prof Peter Blaha, Thank you very much for your detailed explanation.
Many thanks, Ding On Mon, 27 Apr 2020 at 4:25 pm, Peter Blaha <pbl...@theochem.tuwien.ac.at> wrote: > For a difference density it is of course necessary that you treat the > same states in the solids and in the atom. > While in an atom this is fairly simple, because each state is classified > by n,l,m (or kappa), for the solid we are missing the "n". We know > easily the "l" (s,p,d,f), but not the principal quantum number n (like > 4p or 5p). > > This can be only be done by comparising with the atom, via the > "knowledge" what a chemist would call "valence and core" states and via > the energies of these states. > > a) execute: x lstart -sigma > b) This creates a case.inst_sigma input file, where the "P" indicates > to you, which atomic densities are plotted. > c) Look into case.outputst to see their energies (and in particular > those of lower lying states (semi-core states) which have a "T" > indicating that they are included in the solid as "valence" and some of > them must be cut away. > d) now look at your scf1 file (both the E-parameters as you showed us, > but also the eigenvalues. Sometimes also the band-ranges in case.output2 > are helpful.: > > > ATOMIC SPHERE DEPENDENT PARAMETERS FOR ATOM Ce > > :e__0001: OVERALL ENERGY PARAMETER IS 0.5943 > > OVERALL BASIS SET ON ATOM IS LAPW > > :E2_0001: E( 2)= 0.5943 > > APW+lo > > :E2_0001: E( 2)= -6.9944 E(BOTTOM)= -7.002 E(TOP)= -6.987 > 1 2 170 > > LOCAL ORBITAL > > :E0_0001: E( 0)= 0.5943 > > APW+lo > > :E0_0001: E( 0)= -1.8665 E(BOTTOM)= -2.558 E(TOP)= -1.175 > 4 5 176 > > LOCAL ORBITAL > > :E1_0001: E( 1)= 0.9943 > > APW+lo > > :E1_0001: E( 1)= -0.4363 E(BOTTOM)= -1.448 E(TOP)= 0.575 > 3 4 197 > > LOCAL ORBITAL > > :E3_0001: E( 3)= 0.6959 E(BOTTOM)= 0.466 E(TOP)= 0.925 > 0 1 123 > > APW+lo > > There should be Ce-d states around -7 Ry. Compare to the outpust file > and you should see that these are 4d states (they are a bit lower in the > atom) and thus "not valence", so they sould be cut away. > You can do the same for Ce-s (5s) and finally 5p. The latter are at -1.6 > in the atom, but according to your list at -0.4 in the solid. > > e) So look again at the eigenvalues of case.output1 or the band ranges > in output2 and you should find a solution: most likely your emin > should be around -0.2 or so, i.e. in the "gap" between the real valence > states (B-sp Ce-4f,5d,6sp) and the semicore states as identified above. > > PS: In some cases, the "automatic" procedure with "x lstart -sigma" may > not work. Take a Ce-oxide, there will be O-2s states at LOWER energy > than these Ce-5p states and you CANNOT select an EMIN, which "keeps" the > O-2s but cuts away the Ce-5p. In such cases you have to explicitly > include / exlude certain states in the atom (eg. edit case.inst_sigma > and replace the "P" by "N" for the O-2s states, rerun: > lstart lstart.def (where lstart.def should contain: case.inst_sigma, > not just case.inst). > > Am 27.04.2020 um 04:38 schrieb Ding Peng: > > Dear WIEN2k experts, > > > > I am trying to calculate the difference electron density of CeB6, which > has a space group of Pm-3m, by WIEN2k (16.04). After I finished running SCF > cycles (I used non-magnetic calculation GGA+U calculation, runsp_c_lapw, by > forcing the magnetic moment in a spin-polarised setup to zero), I followed > the electron density calculation process: > > > > 1) check case.scf1, it shows > > > > --------------------------------------------------------------------- > > LDA+U potential added for atom type 1 L= 3 spin up > > :LMAX-WF: 10 Non-Spherical LMAX: 4 > > > > ATOMIC SPHERE DEPENDENT PARAMETERS FOR ATOM Ce > > :e__0001: OVERALL ENERGY PARAMETER IS 0.5943 > > OVERALL BASIS SET ON ATOM IS LAPW > > :E2_0001: E( 2)= 0.5943 > > APW+lo > > :E2_0001: E( 2)= -6.9944 E(BOTTOM)= -7.002 E(TOP)= -6.987 1 > 2 170 > > LOCAL ORBITAL > > :E0_0001: E( 0)= 0.5943 > > APW+lo > > :E0_0001: E( 0)= -1.8665 E(BOTTOM)= -2.558 E(TOP)= -1.175 4 > 5 176 > > LOCAL ORBITAL > > :E1_0001: E( 1)= 0.9943 > > APW+lo > > :E1_0001: E( 1)= -0.4363 E(BOTTOM)= -1.448 E(TOP)= 0.575 3 > 4 197 > > LOCAL ORBITAL > > :E3_0001: E( 3)= 0.6959 E(BOTTOM)= 0.466 E(TOP)= 0.925 0 > 1 123 > > APW+lo > > > > ATOMIC SPHERE DEPENDENT PARAMETERS FOR ATOM B > > :e__0002: OVERALL ENERGY PARAMETER IS 0.5943 > > OVERALL BASIS SET ON ATOM IS LAPW > > :E0_0002: E( 0)= 0.5943 > > APW+lo > > :E1_0002: E( 1)= 0.5943 > > APW+lo > > --------------------------------------------------------------------- > > > > > > 2) I choose the default value Emin = -1 and rerun LAPW2 calculation > > > > 3) run lstart -sigma to calculate the superposed atomic electron density > > > > 4) run lapw5 and set the option "DIFF" in case.in5 > > > > > > > > > > The result difference electron density map was presented by Xcrysden. I > found very strong electron accumulation (delta rho is positive) near the > core of Ce ions and electron depletion(delta rho is negative) near the core > of B ions. > > > > My questions are: > > > > 1) Does this result makes sense? Because Ce3+ is cation, which should > tend to lose electrons, and therefore delta rho should be negative near the > core of Ce. This contradicts to my difference electron density map. > > > > 2) Is the superposed atomic electron density equivalent to the > superposed atomic electron densities from independent atomic model (IAM)? > Or it is equivalent to the superposition of the atomic electron densities > of ions? > > > > 3) Is it correct to set Emin = -1? I had read the past discussions about > this topic from the Wien2k email list, but still have no idea how to > determine E > <https://www.google.com/maps/search/t+still+have+no+idea+how+to+determine+E?entry=gmail&source=g>min > based on the results in case.scf1. > > > > > > Look forward to the answers. > > > > Many thanks, > > Ding > > > > _______________________________________________ > > Wien mailing list > > Wien@zeus.theochem.tuwien.ac.at > > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html > > > > -- > Peter Blaha > Inst.Materials Chemistry > TU Vienna > Getreidemarkt 9 > A-1060 Vienna > Austria > +43-1-5880115671 > _______________________________________________ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >
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