I suggest you take your time to read this if you have not yet, I am also learning like you. I might try to experiment with you system to see what I get with same pseudopotentials as you used.
http://urania.sissa.it/xmlui/handle/1963/2507 and then look at this tutorial http://www.iiserpune.ac.in/~smr2626/hands_on/week1/july4/ 2016-10-16 11:54 GMT+02:00 Phanikumar Pentyala <phani12.c...@gmail.com>: > Hello QE users > > I want to find U value for CeO2 which is having 81 atoms. I already > calculated this value by using linear response (http://hjklol.mit.edu/ > content/calculating-hubbard-u). I got the U value initially in negative > numbers in this case *diago_thr_init* value was default, so that I > changed *diago_thr_init* to 10^-11 then I got U value as 0.00881. From > literature I found this value should be around 4.5 - 7eV (Phy. Rev. B 75, > 035109, 2007͒). I have some doubts regarding this calculation > > Is that correct, occupations means I took value in the name of *"N of > occupied +U levels" *(i.e sum of Tr[ns(na)] values on all 27 Ce atoms)? > > What is the unit for value I got (0.00881)? (Ry or eV or any other ) > > Is U parameter value depend on number of atoms in unit cell? > > Is there any other mistake I done in my input file ? (input file attached) > > *Conditions I applied in my calculations:* > Surface calculation with vacuum 15A > First three layers relaxed (two oxygen and one ceria layers) remaining are > frozen > > > Thanks in advance and I will be greatly appreciated for your help > > (input file and results of my calculation attached) > > > Phanikumar > Research Scholar > Indian Institute of Technology Kharagpur > India > > _______________________________________________ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum >
_______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum