Only atoms for which you want to compute U should be listed. same thing in the file of positions.
Matteo duchl06 wrote: > Dear Matteo > thanks for your quick reply, so another question as i mentioned in the > former email. > if we have different atoms with different number, how we set the value > of the keyword below > >> ntyp = 1 # number of types of atoms > >> na(1) = 2 # number of atoms per type > or is it only relate to the atom with a nonzero U value. > best regards! > du > > ??2010-04-05 21:48:59??"Matteo Cococcioni" <matteo at umn.edu> ?????? > > > >Dear Du, > > > >the input you found below is to extract the U values from a series of > >scf calculations. > >You can give a look (besides the reference cited below) to the tutorials > >you find in this webpage: > >http://www.quantum-espresso.org/wiki/index.php/QESB09. > >Unfrtunately the value of U is generally not portable and changes > >depending on the invironment of the atom in the > >specific crystal you are considering. the one you cite is a good > >example: Fe in bulk Fe and in FeO. > >So in principles we need to recompute it each time. > > > >hope this helps. > > > >Matteo > > > > > >duchl06 wrote: > >> dear pw users > >> i want to do a calculation of V chain absorb on a plane with DFT+U, > >> but i donot know how to determine the value of U. > >> i found a PPT on the pwscf's media site, they said the value of U > >> could be decised by a linear response approach. > >> but i really donot understand that like the input file resp_mat.in > >> > >> &input_mat > >> ntyp = 1 # number of types of atoms > >> na(1) = 2 # number of atoms per type > >> if we have different type atoms with different number, how we set these? > >> > >> nalfa = 5 # number of perturbations (alpha) > >> filepos = 'pos_sc1' # file containing the atomic positions and the > >> vectors of the unit cell > >> back = 'neutral' # to add a neutralizing ??background??. see PRB 71 > >> 35105 (2005) > >> what does this mean > >> filednda = 'file_sc1' # file containing the names of the files dn*dat > >> n1 = 4 > >> n2 = 4 # number of unit cells in each direction to construct the > >> supercell for > >> n3 = 4 # extrapolation (in this case a 4x4x4 supercell of the SC one) > >> &end > >> > >> and they get the U is about 2.4ev for the iron, and they use 4.3ev for > >> the FeO calculation, > >> we always need a linear response approach to get the U for every system > >> or just a U for a certain pseudopotential (i mean if we get a U for V > >> bulk, then if i could use this value for another system with V atom, > >> like V2O3 etc.) > >> any suggestions or comment would be OK. > >> thanks > >> > >> Du > >> xiaguanying university > >> > >> > >> ------------------------------------------------------------------------ > >> > >> _______________________________________________ > >> Pw_forum mailing list > >> Pw_forum at pwscf.org > >> http://www.democritos.it/mailman/listinfo/pw_forum > >> > > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Matteo Cococcioni Department of Chemical Engineering and Materials Science, University of Minnesota 421 Washington Av. SE Minneapolis, MN 55455 Tel. +1 612 624 9056 Fax +1 612 626 7246 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
