In the second step, what if the total energy changes with the internal structure so that the so-called energy minimum found in step one is no longer a energy minimum?
Yundi 2011/9/26 Ghosh SUDDHASATTWA <ssghosh at igcar.gov.in>: > 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-bounces at 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 > _______________________________________________ > Wien mailing list > Wien at zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > >