Dear QE community, I want to calculate the phonon diseprsion relation of PbTiO3 in the strucutre of R-3c spacegroup. First I did the vc-relax using the experimental lattice parameters. However, the scf calculation fails to converge within 100 iteration and the job exits with error. I have tried changing the mixing_beta to 0.3 and mixing_ndim to 10, but still fails. I am a newbie to QE. May someone please give me some advices on this issue?
INPUT file: &control calculation='vc-relax', restart_mode='from_scratch', prefix='PbTiO3', outdir = './tmp/', pseudo_dir = '$PSD_DIR', max_seconds = 4.1D+6 / &system nat = 10 ntyp = 3 ibrav = 5 celldm(1) = 10.037, celldm(4) = 0.53, ecutwfc =60 / &electrons mixing_beta=0.3D0, mixing_ndim=10 / &ions / &cell / ATOMIC_SPECIES Pb 207.2 Pb.pbe-spn-rrkjus_psl.1.0.0.UPF Ti 47.867 Ti.pbe-spn-rrkjus_psl.1.0.0.UPF O 15.999 O.pbe-n-rrkjus_psl.1.0.0.UPF ATOMIC_POSITIONS {alat} Pb 0.25 0.25 0.25 Pb 0.75 0.75 0.75 Ti 0.00 0.00 0.00 Ti 0.50 0.50 0.50 O 0.62351014 0.87648986 0.25000000 O 0.37648986 0.12351014 0.75000000 O 0.87648986 0.25000000 0.62351014 O 0.12351014 0.75000000 0.37648986 O 0.25000000 0.62351014 0.87648986 O 0.75000000 0.37648986 0.12351014 K_POINTS AUTOMATIC 15 15 15 0 0 0 Thanks in advance. Fermin
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