Hi, The struct file that I used is attached. For my purpose, the size of the unit cell was large enough to avoid spurious interactions between neighbouring cells. Note that a, b and c are different in order to avoid to high symmetry.
F. Tran On Mon, 29 Dec 2014, Muhammad Sajjad wrote:
Dear Prof. Marks and F. TranThank you so much for your helpful suggestions. I was already doing the spin polarization calculations. I have got the convergence by using mixing factor 0.1, starting calculation with PRATT and then switched to MSR1 after 7 cycles, and the command runsp_lapw -cc 0.00001 -in1ef -i 150 The obtained magnetic moment was 2.00009. Dear Tran I would really appreciate if you share some more details about case.struct file. It will definitely be helpful for me as well as for others. Kind Regards Dr. Sajjad On Mon, Dec 29, 2014 at 3:50 AM, <t...@theochem.tuwien.ac.at> wrote: The calculation for an isolated atom with a code which uses periodic boundary conditions (like WIEN2k) is not trivial. This is what I have done recently for most atoms of the periodic table (excluding f-systems), and for some of the transition-metal atoms this was extremely difficult to achieve convergence. A few hints (that I used): 1) It is important (and necessary depending on the atom) to reduce the symmetry from cubic to, e.g., orthorhombic to be able to access the electronic configuration with the lowest energy (this is the procedure followed by several research groups like VASP for instance). If necessary I can give more details about the case.struct that I used. 2) lapw0 requires a lot of memory, while lapw1 requires both memory and time. To reduce computer time for lapw1, I was using iterative digonalization (this was my command for all atoms): runsp_lapw -ec 0.0001 -cc 0.0001 -it -i 1000 -NI 3) For the Ni atom the magnetic moment should be 2: :MMTOT: SPIN MAGNETIC MOMENT IN CELL = 2.00238 4) I was using the default setting for mixer. F. Tran On Sun, 28 Dec 2014, Laurence Marks wrote: Also, only 1 k-point (Gamma), an RMT and RKMax similar to what you use for bulk Ni, particularly as I assume you are doing the calculation to get an enthalpy of formation. You may have to use the mpi versions as it is probably too large for a non-mpi run. If you are doing WC+U (or -ineece) the U (or on-site hybrid) removes the phase transition so convergence should be simple. Straight WC is not a simple calculation because the physics for an isolated Ni atom is wrong. With wrong physics there is in fact no guarantee that the calculation will ever converge! ___________________________ Professor Laurence Marks Department of Materials Science and Engineering Northwestern University www.numis.northwestern.edu MURI4D.numis.northwestern.edu Co-Editor, Acta Cryst A "Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Gyorgi On Dec 28, 2014 11:47 AM, "Laurence Marks" <l-ma...@northwestern.edu> wrote: You almost certainly need to run spin polarized, probably MSR1 (GREED 0.1), TEMPS (room temp). The convergence is complicated for WC (& simple GGAs) due to an electronic phase transition between sp & d occupation near the fixed point. ___________________________ Professor Laurence Marks Department of Materials Science and Engineering Northwestern University www.numis.northwestern.edu MURI4D.numis.northwestern.edu Co-Editor, Acta Cryst A "Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Gyorgi On Dec 28, 2014 10:47 AM, "Muhammad Sajjad" <sajja...@gmail.com> wrote: Dear Users I am running SCF calculation for Ni with lattice constant of 30 Bohr and using WC-GGA. The calculation is not converging even upto 100 iterations and more. To solve the problem I have performed following steps switched to TEMPS = 0.005 from TETRA Changed MSR1 to PRATT changed mixing factor (increase and decrease from 0.2) Thanking in advance. Dr. Sajjad _______________________________________________ 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
Ni P LATTICE,NONEQUIV.ATOMS: 1 MODE OF CALC=RELA unit=ang 18.897269 18.991755 19.086241 90.000000 90.000000 90.000000 ATOM -1: X=0.00000000 Y=0.00000000 Z=0.00000000 MULT= 1 ISPLIT= 8 Ni NPT= 781 R0=0.00005000 RMT= 1.8000 Z: 28.0 LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 8 NUMBER OF SYMMETRY OPERATIONS -1 0 0 0.00000000 0-1 0 0.00000000 0 0-1 0.00000000 1 -1 0 0 0.00000000 0-1 0 0.00000000 0 0 1 0.00000000 2 -1 0 0 0.00000000 0 1 0 0.00000000 0 0-1 0.00000000 3 -1 0 0 0.00000000 0 1 0 0.00000000 0 0 1 0.00000000 4 1 0 0 0.00000000 0-1 0 0.00000000 0 0-1 0.00000000 5 1 0 0 0.00000000 0-1 0 0.00000000 0 0 1 0.00000000 6 1 0 0 0.00000000 0 1 0 0.00000000 0 0-1 0.00000000 7 1 0 0 0.00000000 0 1 0 0.00000000 0 0 1 0.00000000 8
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