Dear QE Friends: An excerpt of my QE input is appended by the end of this message.
I ran QE with "space_group = 15" and "ATOMIC_POSITIONS crystal_sg" to do 'relax' calculation. It seems to me QE does the following. 1. Initially, QE uses space_group and the 7 inequivalent atoms in ATOMIC_POSITIONS to produce 24 atoms in the crystal unit cell. 2. In each subsequent geometric step of the 'relax' calculation, the 24 atoms are moved independently according to the forces acting on each atom. Therefore, at the end of the 'relax' calculation, the space_group=15 symmetry is not always preserved. My question is that Can QE only move the 7 inequivalent atoms and use space_group symmetry to construct the other 17 atoms for next geometric step? This way, the space_group symmetry will be preserved at the end of the simulation. Thank you in advance. Best Regards, Tsung-Lung Li ------------------------------------------------------------------ &control calculation = 'relax' restart_mode = 'from_scratch' / &system space_group = 15 celldm(1) = 11.86181088389489 ! bohr celldm(2) = 2.41851202803887 celldm(3) = 0.903616377250279 celldm(5) = -0.408489773780522 ntyp = 4 nat = 7 / ATOMIC_SPECIES Ca 40.0780000000 Ca_pbe_v1.uspp.F.UPF S 32.0650000000 S_pbe_v1.2.uspp.F.UPF O 15.9994000000 O.pbe-n-kjpaw_psl.0.1.UPF H 1.0079000000 H.pbe-rrkjus_psl.0.1.UPF ATOMIC_POSITIONS crystal_sg Ca 0.00000 0.17050 0.25000 S 0.00000 0.32727 0.75000 O 0.08319 0.27218 0.59103 O 0.19997 0.38195 0.91298 O -0.20823 0.06826 -0.07831 H -0.25800 0.08700 -0.23400 H -0.24400 0.02000 -0.07700 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
