Dear Jibiao, I don’t know whether this is the source of your problem, but your ecutrho seems a little low. Typically for US PPs it is 8 or 10 times bigger than ecutrho. Yours is barely above 4x. This is particularly important if your Se PP has d states. Have you studied the convergence of forces and stresses with ecutrho?
Best, Matteo On Nov 23, 2018, at 10:32 AM, jibiaoli <[email protected]<mailto:[email protected]>> wrote: Dear QE users and developers, Recently I used vc-relax to optimize Se in the honeycomb structure, but the unit cell goes larger and larger without convergence. To me there must be something wrong with my calculations. Do you have any idea to get everything right? Best Jibiao Li Yangtze Normal University, China &CONTROL calculation = 'vc-relax' , restart_mode = 'from_scratch' , outdir = './' , pseudo_dir = '/home/jibiaoli/pseudo/' , prefix = 'Se_hc' , disk_io = 'high' , / &SYSTEM ibrav = 4, celldm(1) = 4.7126, celldm(3) = 8.41, nat = 2, ntyp = 1, ecutwfc = 41 , ecutrho = 180 , occupations = 'smearing' , degauss = 0.05D0 , smearing = 'methfessel-paxton' , vdw_corr = 'grimme-d2' , / &ELECTRONS mixing_beta = 0.3D0 , diagonalization = 'david' , / &IONS ion_dynamics = 'bfgs' , / &CELL cell_dynamics = 'bfgs' , cell_dofree = '2Dxy' , / ATOMIC_SPECIES Se 78.96100 Se.pbe-van.UPF ATOMIC_POSITIONS angstrom Se 1.246899765 0.719897900 0.000000000 Se 0.000000000 0.000000000 0.000000000 0 0 0 K_POINTS automatic 9 9 1 0 0 0 _______________________________________________ users mailing list [email protected]<mailto:[email protected]> https://lists.quantum-espresso.org/mailman/listinfo/users ************************************************ Matteo Cococcioni Theory and Simulation of Materials École Polytechnique Fédérale de Lausanne
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