Re: [Wien] SCF Convergence with mBJ
Are you using wien2k_14.x ??? Am 05.12.2014 18:20, schrieb Qasim Mahmood: Dear User Could you please let me know what changes we can make to converge our calculations with mBJ ( at50% doping). I have done almost all the steps that i know, like to change mixing factor, switch to MSRI from PRATT within 6 to 10 cycles, use dense k-mesh etc. My system is a magnetic ternary alloy where the magnetic ion is Co. With many thanks and true regards */ Mr.Qasim Mahmood /* */Ph.D Schollar, PU,Lahore,Pakistan/* ___ 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
Re: [Wien] SCF Convergence with mBJ
Hi, Magnetic systems can be very difficult to converge and even more with mBJ. But, without knowing more details it's difficult to help you. Which criteria of convergence for energy (-ec) and charge (-cc) are you using? During how many iterations did you let the calculation running? You could also do "grep :DIS case.scf" to show use how the distance charge behaves. F. Tran On Fri, 5 Dec 2014, Qasim Mahmood wrote: Dear User Could you please let me know what changes we can make to converge our calculations with mBJ ( at50% doping). I have done almost all the steps that i know, like to change mixing factor, switch to MSRI from PRATT within 6 to 10 cycles, use dense k-mesh etc. My system is a magnetic ternary alloy where the magnetic ion is Co. With many thanks and true regards Mr.Qasim Mahmood Ph.D Schollar, PU,Lahore,Pakistan ___ 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
[Wien] SCF Convergence with mBJ
Dear User Could you please let me know what changes we can make to converge our calculations with mBJ ( at50% doping). I have done almost all the steps that i know, like to change mixing factor, switch to MSRI from PRATT within 6 to 10 cycles, use dense k-mesh etc. My system is a magnetic ternary alloy where the magnetic ion is Co. With many thanks and true regards *Mr.Qasim Mahmood* *Ph.D Schollar, PU,Lahore,Pakistan* ___ 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
Re: [Wien] Supercell structure co-ordinates are different in Wien2k and PHON
I am not familar with VASP and this is the Wien2k Forum here, but I know that there is no need to give the name of the atoms in POSCAR the line 16 16 16 means 16 atoms of the first kind 16 of the scond and 16 of the third and there are 3 times 16 positions in the list and the lattice is cubic primitive as seen from the matrix the result is something like XYZ instead of X2YZ I guess PHON gave the correct answer on the wrong question. (Remember, the ERROR is always sitting 30 cm (1ft. for Americans) in front of your monitor ;-) I like much more to use the correct space groups then to give the matrix by hand. Phonophy suggest for Wien2k to use P 1 in cases where the construction of the Hellman Feynman forces failes. I have only experience with Wien2k and Phonon of Parlinsky and had no problems with the produced struct files with different superstructure sizes. Ciao Gerhard DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy: "I think the problem, to be quite honest with you, is that you have never actually known what the question is." Dr. Gerhard H. Fecher Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University 55099 Mainz and Max Planck Institute for Chemical Physics of Solids 01187 Dresden Von: wien-boun...@zeus.theochem.tuwien.ac.at [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Lyudmila Dobysheva [lyuk...@mail.ru] Gesendet: Freitag, 5. Dezember 2014 09:20 An: A Mailing list for WIEN2k users Betreff: Re: [Wien] Supercell structure co-ordinates are different in Wien2k and PHON On 04.12.2014 01:22, venkatesh chandragiri wrote: > The initial structure file contains 12 > atoms with a primitive type.Now, I have generated 2x2x2 supercell using > the same struct file (contains 12 number of atoms) in both Wien2k and > PHON programs. For Wien2k, depending on the selection of the output > lattice (FCC, BCC, primitive), the number of atoms would change. > For primitive = 96 atoms, BCC = 48 atoms, FCC = 24 atoms. I have a feeling that some misunderstanding exists here: all three variants of WIEN2k contain 96 atoms (which is correct), your SPOSCAR file contains only positions which correspond to iron atoms in the FE2VAl.struct file. No information on the type of atoms is in the SPOSCAR file at all. Start from this - here is something wrong, and then think about symmetry P1 also. Best wishes Lyudmila Dobysheva -- Phys.-Techn. Institute of Ural Br. of Russian Ac. of Sci. 426001 Izhevsk, ul.Kirova 132 RUSSIA -- Tel.:7(3412) 218988(office), 722529(Fax) E-mail: l...@ftiudm.ru, lyuk...@mail.ru (office) lyuk...@gmail.com (home) Skype: lyuka17 (home), lyuka18 (office) http://fti.udm.ru/content/view/25/103/lang,english/ -- ___ 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 ___ 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
Re: [Wien] Supercell structure co-ordinates are different in Wien2k and PHON
On 05.12.2014 15:28, Fecher, Gerhard wrote: > c) and make a 1x1x1 supercell with F lattice and afterwards > a 2x2x2 supercell with P lattice you will have the cell with > 128 inequivalent atoms. On 05.12.2014 12:20, Lyudmila Dobysheva wrote:> variants of WIEN2k contain 96 atoms (which is correct), Yes, this is wrong in my letter. The wien2k file contains overall 128 atoms (16x2x2x2), but > your SPOSCAR file contains only positions which correspond to iron atoms > in the FE2VAl.struct file. and not all positions of Fe atoms are given there. Something wrong happened when you made the SPOSCAR file. Best wishes Lyudmila Dobysheva -- Phys.-Techn. Institute of Ural Br. of Russian Ac. of Sci. 426001 Izhevsk, ul.Kirova 132 RUSSIA -- Tel.:7(3412) 218988(office), 722529(Fax) E-mail: l...@ftiudm.ru, lyuk...@mail.ru (office) lyuk...@gmail.com (home) Skype: lyuka17 (home), lyuka18 (office) http://fti.udm.ru/content/view/25/103/lang,english/ -- ___ 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
Re: [Wien] Supercell structure co-ordinates are different in Wien2k and PHON
Yes, if you use the cell with 12 (NONEQUIV.ATOMS !) and split the position of one of the Fe atoms it's ok thus you can move one of the V, AL and Fe atoms each independent of their equilibrium positions In the same way you may split the position of one of the Fe atoms in the larger supercells. (It's not a preferential method to do that by hand in the struct files) The cell has indeed not 12 but 16 atoms (the 4 iron atoms appear twice), that is, it has 12 inequivalent positions occupied by overall 16 atoms. If you start withthe structure in space group F m-3m (225) a) and make a 1x1x1 supercell with F lattice (result is a cell with 4 positions) and afterwards from this a 1x1x1 cell with P lattice you will have the cell with 16 inequivalent atoms. b) and make a 2x2x2 supercell with P lattice you will have the cell with 96 inequivalent atoms (again all Fe appear twice). c) and make a 1x1x1 supercell with F lattice and afterwards a 2x2x2 supercell with P lattice you will have the cell with 128 inequivalent atoms. (use sgroup to check that it finds back your initial structure, in all cases) I guess the use of the P, F, and B lattices is not realy intuitive. Example: The primitive cell of the Fe2VAl compound is fcc with a basis of 4 atoms (in the detailed F m-3m space group (225) you have only "3 independent atoms" occupying the 4a, 4b, 8c positions, 4+4+8=16) in the fcc lattice you need, however, to occupy 4 positions with the 4 atoms (2+1+1), those positions are: 0,0,0, 1/4,1/4,1/4, 1/2,1/2,1/2, and 3/4,3/4,3/4,3/4 ! (note: this corresponds in 216 for example to 4a, 4b, 4c, 4d) the primitive cell has not a cubic shape but it is rhombohedral with a1=a2=a3 = ac/sqrt(2) and alpha=beta=gamma=60°, where ac is the lattice constant of the cube. (Try it, use a P lattice with those parameters and the 4 positions occupied and you will see that sgroup finds F m-3m, with the 3 iequivalent positions occupied) We learn: NONEQUIV.ATOMS means NONEQUIValent POSITIONS but not number of atoms in the cell. My remark on P1 was that you cannot use the 12 atoms cell directly but the one with 16 atoms produced by (a) (this is a setup in P1 symmetry). There is no need to have P1 before running supercell, see above. If you keep the atoms in the high symmetry positions then the forces will be Zero (did you ever check youre output and its meaning ?) To find the forces you need to move the inequivalent atoms one by one from their equilibrium positions to calculate the forces. (I would not do that by hand but its a good thing to play with and to see whats going on with symmetry and forces.) These forces can then be used to calculate the phonons. (by the way, don't use mini positions or MSR1a, then the forces will again be zero, hopefully, otherwise youre structure is not stable)) Note: I did not check if besides the monoclinic space group P m (6) something orthorhombic may also describe the output of 1x1x1 supercell for P lattice. It is interesting to note that the structure can also be described by the primitive cubic space group P m-3m and occupying the 8g (Fe), 1b, 3a (V) and 1a, 3c (Al) positions (this are 5 independent positions). (also interesting , this does not work directly with P, use 221 and save it, then change to P, structgen in W2web tells "Error - incorrect space group symbol", just continue and sgroup finds again F m-3m) We learn: P is not equal to P, unfortunately. Ciao Gerhard DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy: "I think the problem, to be quite honest with you, is that you have never actually known what the question is." Dr. Gerhard H. Fecher Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University 55099 Mainz and Max Planck Institute for Chemical Physics of Solids 01187 Dresden Von: wien-boun...@zeus.theochem.tuwien.ac.at [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von venkatesh chandragiri [venkyphysicsi...@gmail.com] Gesendet: Freitag, 5. Dezember 2014 05:22 An: wien@zeus.theochem.tuwien.ac.at Betreff: Re: [Wien] Supercell structure co-ordinates are different in Wien2k and PHON Dear Dr.Gerhard Thanks for your quick answer. According to you, I should start with P1 cell, which could also obtained by splitting the atomic positions of Fe-atoms of this pm(6) space group (12 atoms). Further, In your mail, I have seen the statement "For Phonon calculations one would need the P 1 cell, otherwise one moves (in certain cases) 2 or more atoms at once out of there equilibrium positions (here Fe atoms)" Can please, elaborate it (why one needs P1 cell as starting structure (before doing supercell)) for phonon calculations...why the atoms go out of their equilibrium positions, if i start with other than P1 symmetry. Thanking you and looking forward to your answers Sincerely, Ch. Ven
Re: [Wien] about EELS
Hi Qingping, looks like you have it mostly figured out already: 1/ These are all the same. 2/ That's correct. You'll find an estimate of the onset energy itself in case.outputelnes (or in case.outputc), but you often have to shift them a bit to align with the experiment anyway. Chemical shifts however are typically much more accurate than the absolute values of edge onsets. 3/ That's right. Cheers, Kevin On Fri, Dec 5, 2014 at 4:49 AM, Meng, Qingping wrote: > Dear wien2k's users, > I have some questions about calculated EELS. > 1) why the title of x-coordinate in some EElS figures use Energy-loss, and > sometimes use Energy above Fermi, or Energy above threshold? Are they > different? > 2) 0 point of x-coordinate is the value of edge onset? > 3) if I want to calculate L2 L3 peak, I need input n=2, l=1 in input file. > Thank you. > Best wishes, > Qingping > > ___ > 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 > > ___ 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
Re: [Wien] Supercell structure co-ordinates are different in Wien2k and PHON
On 04.12.2014 01:22, venkatesh chandragiri wrote: The initial structure file contains 12 atoms with a primitive type.Now, I have generated 2x2x2 supercell using the same struct file (contains 12 number of atoms) in both Wien2k and PHON programs. For Wien2k, depending on the selection of the output lattice (FCC, BCC, primitive), the number of atoms would change. For primitive = 96 atoms, BCC = 48 atoms, FCC = 24 atoms. I have a feeling that some misunderstanding exists here: all three variants of WIEN2k contain 96 atoms (which is correct), your SPOSCAR file contains only positions which correspond to iron atoms in the FE2VAl.struct file. No information on the type of atoms is in the SPOSCAR file at all. Start from this - here is something wrong, and then think about symmetry P1 also. Best wishes Lyudmila Dobysheva -- Phys.-Techn. Institute of Ural Br. of Russian Ac. of Sci. 426001 Izhevsk, ul.Kirova 132 RUSSIA -- Tel.:7(3412) 218988(office), 722529(Fax) E-mail: l...@ftiudm.ru, lyuk...@mail.ru (office) lyuk...@gmail.com (home) Skype: lyuka17 (home), lyuka18 (office) http://fti.udm.ru/content/view/25/103/lang,english/ -- ___ 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
