How about trying to fix the movement for BN-sheet and just move H atoms. The BN-sheet may achieve a concavity during "relax" process. For the absorption of H2, the concavity will vanish and a plane-BN finally be obtained. But for single H atom, I am not sure whether one can ignore such an effect. By the way, is it reasonable that only one H atom was absorped instead of diatom H2 molecule?
-- GAO Zhe CMC Lab, Materials Science & Engineering Department, Seoul National University, South Korea At 2012-04-27 09:20:20,"Cao TF" <tfcao at theory.issp.ac.cn> wrote: Dear QE users Recently, I have done some calculation of BN sheet with hydrogen atoms adsorbed on it. The problem is that when I let hydrogen atoms adsorb on the N atoms. The calculation is hard to converge. Although, I have changed mixing_beta and the number of K points. The problem have not been solved. Dose anyone have some experience on such kind of calculations? Any suggestions will be greatly appreciated. Here is my input file. &CONTROL title = 'graphene layer' , calculation = 'relax' , restart_mode = 'restart' , outdir = './tmp' , pseudo_dir = '/lustre/ISSP2/tfcao/pseudo' , prefix = 'graphene' , tprnfor = .TRUE. , nstep = 400 , / &SYSTEM ibrav = 8 , a = 15.026832 , b = 13.014 , c = 15.0 , nat = 74 , ntyp = 3 , starting_magnetization(1) = 0.5 , occupations = 'smearing' , nosym = .TRUE. , degauss = 0.005 , smearing = 'mp' , nspin = 2 , ecutwfc = 30.0 , ecutrho = 300.0 , / &ELECTRONS conv_thr = 1.0d-7 , mixing_mode = 'local-TF' , mixing_beta = 0.1 , diagonalization = 'cg' , / &IONS ion_dynamics = 'bfgs' , pot_extrapolation = 'atomic' , / ATOMIC_SPECIES B 10.811 B.pbe-n-van.UPF N 14.00674 N.pbe-rrkjus.UPF H 1.00000 H.pbe-rrkjus.UPF ATOMIC_POSITIONS crystal ATOMIC_POSITIONS crystal N 0.0000000 0.0000000 0.50000000 0 0 0 B 0.0000000 0.11111100 0.50000000 N 8.33330005E-02 0.16666700 0.50000000 B 8.33330005E-02 0.27777800 0.50000000 N 0.0000000 0.33333299 0.50000000 B 0.0000000 0.44444400 0.50000000 N 8.33330005E-02 0.50000000 0.50000000 B 8.33330005E-02 0.61111099 0.50000000 N 0.0000000 0.66666597 0.50000000 B 0.0000000 0.77777696 0.50000000 N 8.33330005E-02 0.83333296 0.50000000 B 8.33330005E-02 0.94444394 0.50000000 N 0.16666700 0.0000000 0.50000000 B 0.16666700 0.11111100 0.50000000 N 0.25000000 0.16666700 0.50000000 B 0.25000000 0.27777800 0.50000000 N 0.16666700 0.33333299 0.50000000 B 0.16666700 0.44444400 0.50000000 N 0.25000000 0.50000000 0.50000000 B 0.25000000 0.61111099 0.50000000 N 0.16666700 0.66666597 0.50000000 B 0.16666700 0.77777696 0.50000000 N 0.25000000 0.83333296 0.50000000 B 0.25000000 0.94444394 0.50000000 N 0.33333400 0.0000000 0.50000000 B 0.33333400 0.11111100 0.50000000 N 0.41666698 0.16666700 0.50000000 B 0.41666698 0.27777800 0.50000000 N 0.33333400 0.33333299 0.50000000 B 0.33333400 0.44444400 0.50000000 N 0.41666698 0.50000000 0.50000000 B 0.41666698 0.61111099 0.50000000 N 0.33333400 0.66666597 0.50000000 B 0.33333400 0.77777696 0.50000000 N 0.41666698 0.83333296 0.50000000 B 0.41666698 0.94444394 0.50000000 N 0.50000101 0.0000000 0.50000000 B 0.50000101 0.11111100 0.50000000 N 0.58333403 0.16666700 0.50000000 B 0.58333403 0.27777800 0.50000000 N 0.50000101 0.33333299 0.50000000 B 0.50000101 0.44444400 0.50000000 N 0.58333403 0.50000000 0.50000000 B 0.58333403 0.61111099 0.50000000 N 0.50000101 0.66666597 0.50000000 B 0.50000101 0.77777696 0.50000000 N 0.58333403 0.83333296 0.50000000 B 0.58333403 0.94444394 0.50000000 N 0.66666800 0.0000000 0.50000000 B 0.66666800 0.11111100 0.50000000 N 0.75000101 0.16666700 0.50000000 B 0.75000101 0.27777800 0.50000000 N 0.66666800 0.33333299 0.50000000 B 0.66666800 0.44444400 0.50000000 N 0.75000101 0.50000000 0.50000000 B 0.75000101 0.61111099 0.50000000 N 0.66666800 0.66666597 0.50000000 B 0.66666800 0.77777696 0.50000000 N 0.75000101 0.83333296 0.50000000 B 0.75000101 0.94444394 0.50000000 N 0.83333498 0.0000000 0.50000000 B 0.83333498 0.11111100 0.50000000 N 0.91666800 0.16666700 0.50000000 B 0.91666800 0.27777800 0.50000000 N 0.83333498 0.33333299 0.50000000 B 0.83333498 0.44444400 0.50000000 N 0.91666800 0.50000000 0.50000000 B 0.91666800 0.61111099 0.50000000 N 0.83333498 0.66666597 0.50000000 B 0.83333498 0.77777696 0.50000000 N 0.91666800 0.83333296 0.50000000 B 0.91666800 0.94444394 0.50000000 H 0.50000000 0.66666600 0.56900670 H 0.66666800 0.33333300 0.56900670 K_POINTS {automatic} 8 8 1 0 0 0 ====================================================================== Teng Fei Cao ====================================================================== Research Laboratory for Computational Materials Sciences, Instutue of Solid State Physics,the Chinese Academy of Sciences, P.O.Box 1129, Hefei 230031, P.R.China Tel: 86-551-5591464-326(office) Fax: 86-551-5591434 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120427/ebad4973/attachment.htm