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 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20100405/e47eadbf/attachment-0001.htm
