<div style="line-height:1.7;color:#000000;font-size:14px;font-family:arial">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.<br>By the way, is it reasonable that only one H atom was absorped instead of diatom H2 molecule?<br><br><div>--<br>GAO Zhe<br>CMC Lab, Materials Science & Engineering Department,<br>Seoul National University, South Korea<br>        
 </div><div id="divNeteaseMailCard"></div><br>At 2012-04-27 09:20:20,"Cao TF" <tfcao@theory.issp.ac.cn> wrote:<br> <blockquote id="isReplyContent" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">




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<div>Dear QE users
<br>
   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.
<br>
&CONTROL
<br>
     title = 'graphene layer' ,
<br>
     calculation = 'relax' ,
<br>
     restart_mode = 'restart' ,
<br>
     outdir = './tmp' ,
<br>
     pseudo_dir = '/lustre/ISSP2/tfcao/pseudo' ,
<br>
     prefix = 'graphene' ,
<br>
     tprnfor = .TRUE. ,
<br>
     nstep = 400 ,
<br>
 /
<br>
 &SYSTEM
<br>
     ibrav = 8 ,
<br>
     a = 15.026832 , b = 13.014 , c = 15.0 ,
<br>
     nat = 74 ,
<br>
     ntyp = 3 ,
<br>
     starting_magnetization(1) = 0.5 ,
<br>
     occupations = 'smearing' ,
<br>
     nosym = .TRUE. ,
<br>
     degauss = 0.005 ,
<br>
     smearing = 'mp' ,
<br>
     nspin = 2 ,
<br>
     ecutwfc = 30.0 ,
<br>
     ecutrho = 300.0 ,
<br>
 /
<br>
 &ELECTRONS
<br>
     conv_thr = 1.0d-7 ,
<br>
     mixing_mode = 'local-TF' ,
<br>
     mixing_beta = 0.1 ,
<br>
     diagonalization = 'cg' ,
<br>
 /
<br>
 &IONS
<br>
     ion_dynamics = 'bfgs' ,
<br>
     pot_extrapolation = 'atomic' ,
<br>

<br>
/
<br>
 ATOMIC_SPECIES
<br>
  B   10.811    B.pbe-n-van.UPF
<br>
  N   14.00674  N.pbe-rrkjus.UPF
<br>
  H   1.00000   H.pbe-rrkjus.UPF
<br>
ATOMIC_POSITIONS crystal
<br>
ATOMIC_POSITIONS crystal
<br>
 N   0.0000000       0.0000000      0.50000000  0  0  0
<br>
 B   0.0000000      0.11111100      0.50000000
<br>
 N  8.33330005E-02  0.16666700      0.50000000
<br>
 B  8.33330005E-02  0.27777800      0.50000000
<br>
 N   0.0000000      0.33333299      0.50000000
<br>
 B   0.0000000      0.44444400      0.50000000
<br>
 N  8.33330005E-02  0.50000000      0.50000000
<br>
 B  8.33330005E-02  0.61111099      0.50000000
<br>
 N   0.0000000      0.66666597      0.50000000
<br>
 B   0.0000000      0.77777696      0.50000000
<br>
 N  8.33330005E-02  0.83333296      0.50000000
<br>
 B  8.33330005E-02  0.94444394      0.50000000
<br>
 N  0.16666700       0.0000000      0.50000000
<br>
 B  0.16666700      0.11111100      0.50000000
<br>
 N  0.25000000      0.16666700      0.50000000
<br>
 B  0.25000000      0.27777800      0.50000000
<br>
 N  0.16666700      0.33333299      0.50000000
<br>
 B  0.16666700      0.44444400      0.50000000
<br>
 N  0.25000000      0.50000000      0.50000000
<br>
 B  0.25000000      0.61111099      0.50000000
<br>
 N  0.16666700      0.66666597      0.50000000
<br>
 B  0.16666700      0.77777696      0.50000000
<br>
 N  0.25000000      0.83333296      0.50000000
<br>
 B  0.25000000      0.94444394      0.50000000
<br>
 N  0.33333400       0.0000000      0.50000000
<br>
 B  0.33333400      0.11111100      0.50000000
<br>
 N  0.41666698      0.16666700      0.50000000
<br>
 B  0.41666698      0.27777800      0.50000000
<br>
 N  0.33333400      0.33333299      0.50000000
<br>
 B  0.33333400      0.44444400      0.50000000
<br>
 N  0.41666698      0.50000000      0.50000000
<br>
 B  0.41666698      0.61111099      0.50000000
<br>
 N  0.33333400      0.66666597      0.50000000
<br>
 B  0.33333400      0.77777696      0.50000000
<br>
 N  0.41666698      0.83333296      0.50000000
<br>
 B  0.41666698      0.94444394      0.50000000
<br>
 N  0.50000101       0.0000000      0.50000000
<br>
 B  0.50000101      0.11111100      0.50000000
<br>
 N  0.58333403      0.16666700      0.50000000
<br>
 B  0.58333403      0.27777800      0.50000000
<br>
 N  0.50000101      0.33333299      0.50000000
<br>
 B  0.50000101      0.44444400      0.50000000
<br>
 N  0.58333403      0.50000000      0.50000000
<br>
 B  0.58333403      0.61111099      0.50000000
<br>
 N  0.50000101      0.66666597      0.50000000
<br>
 B  0.50000101      0.77777696      0.50000000
<br>
 N  0.58333403      0.83333296      0.50000000
<br>
 B  0.58333403      0.94444394      0.50000000
<br>
 N  0.66666800       0.0000000      0.50000000
<br>
 B  0.66666800      0.11111100      0.50000000
<br>
 N  0.75000101      0.16666700      0.50000000
<br>
 B  0.75000101      0.27777800      0.50000000
<br>
 N  0.66666800      0.33333299      0.50000000
<br>
 B  0.66666800      0.44444400      0.50000000
<br>
 N  0.75000101      0.50000000      0.50000000
<br>
 B  0.75000101      0.61111099      0.50000000
<br>
 N  0.66666800      0.66666597      0.50000000
<br>
 B  0.66666800      0.77777696      0.50000000
<br>
 N  0.75000101      0.83333296      0.50000000
<br>
 B  0.75000101      0.94444394      0.50000000
<br>
 N  0.83333498       0.0000000      0.50000000
<br>
 B  0.83333498      0.11111100      0.50000000
<br>
 N  0.91666800      0.16666700      0.50000000
<br>
 B  0.91666800      0.27777800      0.50000000
<br>
 N  0.83333498      0.33333299      0.50000000
<br>
 B  0.83333498      0.44444400      0.50000000
<br>
 N  0.91666800      0.50000000      0.50000000
<br>
 B  0.91666800      0.61111099      0.50000000
<br>
 N  0.83333498      0.66666597      0.50000000
<br>
 B  0.83333498      0.77777696      0.50000000
<br>
 N  0.91666800      0.83333296      0.50000000
<br>
 B  0.91666800      0.94444394      0.50000000
<br>
 H  0.50000000      0.66666600      0.56900670
<br>
 H  0.66666800      0.33333300      0.56900670
<br>
K_POINTS {automatic}
<br>
8 8 1 0 0 0
<br>
======================================================================
<br>
Teng Fei Cao
<br>
======================================================================                                                                                                                                                                                     
<br>
    Research Laboratory for Computational Materials Sciences,
<br>
Instutue of Solid State Physics,the Chinese Academy of Sciences,
<br>
P.O.Box 1129, Hefei 230031, P.R.China
<br>
Tel: 86-551-5591464-326(office)
<br>
Fax: 86-551-5591434                                                                                                                                                                                                                                                                                                                                                    
<br>
   </div>




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