Check which criterion was not met charge, energy, or both. Before trying to sharpen the convergency criteria, check if the number of k-points and plane waves are sufficient to meet that criteria. This is for magnetic systems more critical than for non-magnetic ones.
In systems with more than one kind of magnetic atoms, it also might appear that you have two different magnetic states close together, sometimes it helps already if one monitors the behaviour of the individual moments to see if large fluctuations appear. Check if you have ferrimagnetic solutions with some moments being antiparallel to the others. I had also some rare cases were the charge extrapolation was leading to instable magnetic states and the "from scratch" optimization with dstart (-up, -dn) improved the situation, in such cases you may also need to check and change the initial polarisation of the atoms in the case.inst. In many cases calculations for magnetic states are a matter of experience rather than a straight, fixed recipe. Ciao Gerhard ==================================== Dr. Gerhard H. Fecher Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University 55099 Mainz ________________________________________ Von: wien-bounces at zeus.theochem.tuwien.ac.at [wien-bounces at zeus.theochem.tuwien.ac.at]" im Auftrag von "Ghosh SUDDHASATTWA [ssghosh at igcar.gov.in] Gesendet: Mittwoch, 27. Oktober 2010 10:01 Bis: 'A Mailing list for WIEN2k users' Betreff: Re: [Wien] Querie on the -i switch for iterations_Spin Polarized Cases Thank you Gerhard, My idea was to calculate enthalpy of formation of a typical Laves phase AB2 And for all the individual components I used Run_lapw -cc 0.0001 -ec 0.0001 -so -i 90 -p I thought it might work for AB2 as well. But I did not get a smooth variation of the volume with energy. I also used Run_lapw -cc 0.0001 -ec 0.00001 -in1ef -p which work beautifully for Fe_bcc The idea therefore is two fold; one to get the desired accuracy and the second that nobody should question the result !! SG -----Original Message----- From: wien-boun...@zeus.theochem.tuwien.ac.at [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Gerhard Fecher Sent: Wednesday, October 27, 2010 12:34 PM To: A Mailing list for WIEN2k users Subject: Re: [Wien] Querie on the -i switch for iterations_Spin Polarized Cases Do you realy need the charge convergency -cc 0.0001 for the volume optimization ? What for ? For a rough estimate -ec 0.0001 may be fine, you can sharpen the convergency criteria afterwards. Then try for example -cc 0.001 -ec 0.00001 and increase the k-points (copy the clm files don't use charge extrapolation in the second step) check if the relaxed volume is different. Sometimes a lot of 0's don't help a lot. Ciao Gerhard ==================================== Dr. Gerhard H. Fecher Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University 55099 Mainz ________________________________________ Von: wien-bounces at zeus.theochem.tuwien.ac.at [wien-bounces at zeus.theochem.tuwien.ac.at]" im Auftrag von "Ghosh SUDDHASATTWA [ssghosh at igcar.gov.in] Gesendet: Mittwoch, 27. Oktober 2010 06:45 Bis: 'A Mailing list for WIEN2k users' Betreff: [Wien] Querie on the -i switch for iterations_Spin Polarized Cases Dear Wien2k users, I was trying to volume optimize (some 5 structure changes, 4 atoms per lattice) a cubic case with the command in the optimize.job Runsp_lapw -cc 0.0001 -ec 0.0001 -i 90 -so -p However, in one or two cases, the SCF did not converge. What changes could be made keeping the same accuracy of charge and energy convergence. SUDDHASATTWA GHOSH _______________________________________________ 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