Thank you Dr. Gerhard for the advice. I did as you said and it worked. RegardsJameela FatheemaUniversity of Peshawar On Monday, July 17, 2017, 2:04:35 PM GMT+5, Fecher, Gerhard <fec...@uni-mainz.de> wrote:
you need first to initialize the "low symmetry" structure with the displaced atom(s), and afterwards run the "high" symmetry structure with the atoms placed back (do not accept symmetry changes during initialisation). 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 [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Jameela Fatheema [j.fatheem...@yahoo.com] Gesendet: Montag, 17. Juli 2017 10:11 An: A. Mailing List for WIEN2k Users Betreff: [Wien] symmetry problem for spontaneous polarization Dear all, I am running wien version 14 on ubuntu 16. The purpose of my calculations is to calculate the spontaneous polarization for Bi4Ti3O12 tetragonal structure. I have followed the steps provided by the wien2k UG and the notes that are available on wien2k site. The space group is I4/mmm which genertaes 16 symmetry operations for the structure. For the noncentrosymmetric polarization, i displace the titanium and oxygen atoms in the z-direction, about 0.005. this changes the symmetry to 8 and i get the space group as I4mm. After the total polarization for I4mm is obtained i do the steps as mentioned in the notes and tutorial available. The problem is how do i avoid this symmetry change because as much i understand the symmetry needs to remain the same. If i dont do the initialization for the centrosyymetric calculations it shows the ROTDEF error in dstart which is due to the symmetry difference. Should i make the displacement even more smaller? I will be very thankful for any advice. Regards Jameela Fatheema University of Peshawar. _______________________________________________ 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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