Dear all, I want to calculate the phonon bands of a material with rhombohedral structure using phonopy and QE as the force calculator. I first did a vc-relaxation and obtain the following structure ==== vcrelax.out =========== CELL_PARAMETERS (alat= 10.03700000) 0.483245254 -0.279001778 0.825350540 0.000000000 0.558003555 0.825350540 -0.483245254 -0.279001778 0.825350540
ATOMIC_POSITIONS (crystal) Li 0.250000000 0.250000000 0.250000000 Li 0.750000000 0.750000000 0.750000000 Os 0.000000000 0.000000000 0.000000000 Os 0.500000000 0.500000000 0.500000000 O 0.623428459 0.876571541 0.250000000 O 0.376571541 0.123428459 0.750000000 O 0.876571541 0.250000000 0.623428459 O 0.123428459 0.750000000 0.376571541 O 0.250000000 0.623428459 0.876571541 O 0.750000000 0.376571541 0.123428459 End final coordinates ============================= As phonopy requires the cell parameters to be in the Bohr unit. I multiplied the above CELL_PARAMETERS by the lattice constant 10.037. Then using phonopy, a 2x2x2 supercell is created. I tried to calculate the force in QE for one of the displaced supercells but the calculation does not converge even after 200 cycles. I also tried to reduce the mixing beta but it didn't help. The following is the input file ===== 001.in ================== &control calculation='scf', restart_mode='from_scratch', prefix='001', outdir = './tmp/', pseudo_dir = '/home/QE/espresso-5.1.2/pslibrary.1.0.0/pbe/PSEUDOPOTENTIALS/', max_seconds = 172000 wf_collect = .false. / &system nat = 80 ntyp = 3 ibrav = 0 ecutwfc =60 ecutrho=480 / &electrons mixing_beta=0.3D0, conv_thr=1.D-8 electron_maxstep=200 / &ions / &cell / K_POINTS AUTOMATIC 4 4 4 0 0 0 CELL_PARAMETERS bohr 9.7006599999999992 -5.6006799999999997 16.5680799999999984 0.0000000000000000 11.2013599999999993 16.5680799999999984 -9.7006599999999992 -5.6006799999999997 16.5680799999999984 ATOMIC_SPECIES Li 6.94100 Li.pbe-s-rrkjus_psl.1.0.0.UPF Os 190.23000 Os.pbe-spn-rrkjus_psl.1.0.0.UPF O 15.99940 O.pbe-n-rrkjus_psl.1.0.0.UPF ATOMIC_POSITIONS crystal Li 0.1260000353821472 0.1250000000000000 0.1250000000000000 Li 0.6249999999999999 0.1250000000000000 0.1250000000000000 Li 0.1250000000000000 0.6250000000000000 0.1250000000000000 Li 0.6250000000000000 0.6250000000000000 0.1250000000000000 Li 0.1249999999999999 0.1249999999999999 0.6250000000000000 Li 0.6249999999999999 0.1249999999999999 0.6250000000000000 Li 0.1249999999999999 0.6249999999999999 0.6250000000000000 Li 0.6249999999999998 0.6249999999999999 0.6249999999999999 Li 0.3749999999999999 0.3750000000000000 0.3750000000000000 Li 0.8749999999999999 0.3749999999999999 0.3750000000000000 Li 0.3749999999999999 0.8750000000000000 0.3749999999999999 Li 0.8749999999999999 0.8750000000000000 0.3750000000000000 Li 0.3749999999999998 0.3749999999999999 0.8749999999999999 Li 0.8749999999999998 0.3749999999999999 0.8750000000000000 Li 0.3749999999999998 0.8750000000000000 0.8750000000000000 Li 0.8749999999999998 0.8749999999999999 0.8749999999999999 Os 0.0000000000000000 0.0000000000000000 0.0000000000000000 Os 0.5000000000000000 -0.0000000000000000 -0.0000000000000000 Os -0.0000000000000000 0.5000000000000000 -0.0000000000000000 Os 0.5000000000000000 0.5000000000000000 -0.0000000000000000 Os 0.9999999999999999 0.9999999999999999 0.4999999999999999 Os 0.4999999999999999 0.9999999999999999 0.4999999999999999 Os 0.9999999999999999 0.4999999999999999 0.4999999999999999 Os 0.4999999999999999 0.5000000000000000 0.5000000000000000 Os 0.2499999999999999 0.2500000000000000 0.2500000000000000 Os 0.7499999999999999 0.2500000000000000 0.2500000000000000 Os 0.2499999999999999 0.7500000000000000 0.2500000000000000 Os 0.7500000000000000 0.7500000000000000 0.2500000000000000 Os 0.2499999999999998 0.2499999999999999 0.7499999999999999 Os 0.7499999999999999 0.2499999999999999 0.7500000000000000 Os 0.2499999999999998 0.7500000000000000 0.7499999999999999 Os 0.7499999999999999 0.7500000000000000 0.7500000000000000 O 0.3117142295000000 0.4382857705000000 0.1250000000000000 O 0.8117142294999999 0.4382857705000000 0.1250000000000000 O 0.3117142295000000 0.9382857705000002 0.1250000000000000 O 0.8117142294999999 0.9382857705000001 0.1250000000000000 O 0.3117142294999999 0.4382857704999999 0.6250000000000000 O 0.8117142294999998 0.4382857704999999 0.6250000000000000 O 0.3117142294999999 0.9382857705000001 0.6250000000000000 O 0.8117142294999999 0.9382857705000001 0.6250000000000001 O 0.1882857704999999 0.0617142295000000 0.3749999999999999 O 0.6882857704999999 0.0617142294999999 0.3750000000000000 O 0.1882857704999999 0.5617142295000001 0.3750000000000000 O 0.6882857704999999 0.5617142295000001 0.3750000000000000 O 0.1882857704999999 0.0617142294999999 0.8749999999999999 O 0.6882857704999998 0.0617142294999999 0.8749999999999999 O 0.1882857704999998 0.5617142294999999 0.8749999999999999 O 0.6882857704999998 0.5617142294999999 0.8749999999999999 O 0.4382857704999999 0.1250000000000000 0.3117142294999999 O 0.9382857704999999 0.1250000000000000 0.3117142294999999 O 0.4382857704999999 0.6250000000000000 0.3117142294999999 O 0.9382857705000001 0.6250000000000000 0.3117142295000000 O 0.4382857704999998 0.1249999999999999 0.8117142294999998 O 0.9382857704999998 0.1249999999999999 0.8117142294999998 O 0.4382857704999998 0.6249999999999999 0.8117142294999998 O 0.9382857704999999 0.6250000000000000 0.8117142294999999 O 0.0617142295000000 0.3750000000000000 0.1882857705000000 O 0.5617142294999999 0.3750000000000000 0.1882857705000000 O 0.0617142295000000 0.8750000000000000 0.1882857705000000 O 0.5617142294999999 0.8750000000000000 0.1882857704999999 O 0.0617142294999998 0.3749999999999999 0.6882857704999999 O 0.5617142294999999 0.3750000000000000 0.6882857705000001 O 0.0617142294999998 0.8750000000000000 0.6882857705000001 O 0.5617142294999998 0.8749999999999999 0.6882857704999999 O 0.1249999999999999 0.3117142295000000 0.4382857705000000 O 0.6249999999999999 0.3117142294999999 0.4382857705000000 O 0.1249999999999999 0.8117142294999998 0.4382857705000001 O 0.6249999999999999 0.8117142294999999 0.4382857704999999 O 0.1249999999999998 0.3117142294999999 0.9382857704999999 O 0.6249999999999998 0.3117142294999999 0.9382857704999999 O 0.1249999999999998 0.8117142294999998 0.9382857704999999 O 0.6249999999999998 0.8117142294999998 0.9382857704999999 O 0.3750000000000000 0.1882857705000000 0.0617142295000000 O 0.8750000000000000 0.1882857705000000 0.0617142295000001 O 0.3750000000000000 0.6882857705000001 0.0617142295000000 O 0.8750000000000000 0.6882857705000002 0.0617142295000001 O 0.3749999999999999 0.1882857705000000 0.5617142295000001 O 0.8749999999999999 0.1882857704999999 0.5617142295000001 O 0.3749999999999999 0.6882857705000001 0.5617142295000001 O 0.8749999999999999 0.6882857704999999 0.5617142294999999 ======================================================== Would someone give me some suggestions? Thanks in advance. Best, Fermin
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