Dear Stefaan, I have only given two points. There are in fact 20 points. However, I want to ask you about E0 which more or less matches with the ENE after the SCF cycle with spin orbit coupling.
Suddhasattwa -----Original Message----- From: wien-boun...@zeus.theochem.tuwien.ac.at [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Stefaan Cottenier Sent: Monday, January 11, 2010 1:18 PM To: A Mailing list for WIEN2k users Subject: Re: [Wien] [Wien2k User Group] Volume optimization of Zirconium If this is the entire content of your case.outputeos: > Vol energy de(Birch-Murnaghan) Pressure > 314.2133 -14396.851 0.009235 -1.432 > 314.2133 -14396.848 0.005909 -1.432 then you are make a eos fit through 1 single E(V) point... (actually through two, but they are the same). This doesn't make sense, as there are 4 free parameters in this eos. That's why you find very much rounded values for B and BP: > V0 B(GPa) BP EO > 309.5778 100.0000 5.000 -14396.842 (100 and 5, they are probably just the defaults). Make your eos fit trhough at least 4 data points (5-10 is better). They should all be listed as (:VOL, :ENE) in case.vol. Negative pressures correspond to volumes larger than the equilibrium volume. Stefaan Ghosh SUDDHASATTWA wrote: > Dear Micheal, > As suggested, I did the volume optimization with -5% to +5% > The values are as shown for alpha-zirconium. > V0 B(GPa) BP EO > 309.5778 100.0000 5.000 -14396.842 > Vol energy de(Birch-Murnaghan) Pressure > 314.2133 -14396.851 0.009235 -1.432 > 314.2133 -14396.848 0.005909 -1.432 > ............................................................................ > ; > Are these values possible. > I am really amazed to see the value of pressure which is negative!!!! > The ground state energy is I guess -14396.842. Am I correct? > With spin orbit coupling, the ENE value was -14396.892 which are pretty > close. > > Then why these pressure values are negative. > I seek one more clarification. > In the energy plot curve option, there comes "by using "*". Scf files. > If we want to select a few files and not all the files for plotting, then do > we have to enter the file names with commas separating them? > I ask this question because the points from the previous volume optimization > also are coming in the current plot. > > Thanks > Suddhasattwa Ghosh > > > -----Original Message----- > From: wien-bounces at zeus.theochem.tuwien.ac.at > [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Michael > Fischer > Sent: Sunday, January 10, 2010 3:44 AM > To: wien at zeus.theochem.tuwien.ac.at > Subject: Re: [Wien] [Wien2k User Group] Volume optimization of Zirconium > > Hello, > > I can only guess on this problem, but I am quite sure that changes of > the c/a ratio from -25% to +25% are much too large, since this probably > leads to an overlap of the RMT spheres. > Try a set of calculations for smaller changes of the c/a ratio, e.g. > from -5% to +5%, and make sure beforehand that the RMT spheres do not > overlap in the most strongly distorted structures. > > Regards > Michael > > _______________________________________________ > 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 -- Stefaan Cottenier Center for Molecular Modeling (CMM) Ghent University Technologiepark 903 (2nd floor) BE-9052 Zwijnaarde Belgium http://molmod.Ugent.be email: Stefaan . Cottenier /at/ UGent . be _______________________________________________ Wien mailing list Wien at zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien