Davide, > is your system metallic? > the material I am studying is Li2MnO3. It is an insulator, at low temperature there might exist a weak antiferromagnetic interaction between Mn ions.
In this material I predominantley wanted to calculate the hyperfine interaction between Mn ion and Li nucleus. Therefore I performed spin-polarized calculation. The input file is given below. Nevertheless, I was also interested in the magnitude of Li chemical shifts. &CONTROL calculation = 'scf' , restart_mode = 'from_scratch' , outdir = './scratch/' , pseudo_dir = './pseudo/' , prefix = 'Li2MnO3' , tstress = .true. , tprnfor = .true. , verbosity = 'high' , / &SYSTEM ibrav = 14, A = 4.929200 , B = 8.531500 , C = 5.025100 , cosAB = 0 , cosAC = -0.3311 , cosBC = 0 , nat = 24, ntyp = 3, ecutwfc = 80.0 , ecutrho = 320.0 , occupations = 'smearing' , degauss = 0.02 , smearing = 'gaussian' , nspin = 2 , starting_magnetization(2) = 0.7, / &ELECTRONS conv_thr = 1.0d-10 , mixing_mode = 'plain' , mixing_beta = 0.7 , diagonalization = 'david' , / ATOMIC_SPECIES Li 6.94100 Li_pbe-20090916.UPF Mn 54.93800 Mn.pbe-rrkj-semi-gipaw.UPF O 15.99900 O.pbe-tm-gipaw.UPF ATOMIC_POSITIONS crystal Li 0.000000000 0.500000000 0.000000000 . . . K_POINTS automatic 4 3 4 1 1 1 Gregor