Dear Yundi, What I follow is 1. do volume or c/a, b/a relaxation depending on your structure 2. Use the optimized lattice parameters to do min_lapw 3. Use the optimized lattice parameters and atomic positions to define the supercell in Phonon software 4. import the d45 file from phonon to wien2k 5. run phonon.job in wien2k 6. get the force file and export it to phonon 7. get the phonon dispersion you can use -fc 1.0 in min_lapw as well as in phonon. you can then try -fc 0.50 and then so on SG
_____ From: wien-boun...@zeus.theochem.tuwien.ac.at [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Yundi Quan Sent: Monday, September 26, 2011 3:41 PM To: A Mailing list for WIEN2k users Subject: [Wien] phonon calculation In order to get the correct input structure for phonon calculation, I need to first find the structure with minimal force. How much force is small enough? Is 1.0 mRy/bohr small enough? (I only want to calculate the phonon at gamma point to see whether the system is stable or not at gamma point) Should I first carry out internal structure minimization or crystal structure minimization? Yundi -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20110926/6e0c8afa/attachment.htm>