Dear every one,<br>        I am now trying to calculate the binding energy of Cu@CNT,  I used one cu atom per unit cell, which is cnt (6,6). First I optimized the structure of cnt and the cu@cnt structure, then I calculated the total energy of a single cu atom. I make hand calculations after I get all the total energy result.<br>
       At first I used ultrasoft potential for both cu and cnt, but the result is about -1.6 ev, much different from around -0.1 ev in the literature.<br>      Then I changed the potential to PAW potential, for that is what's used in the literature,  but it seems that the cu@cnt calculation won't converged and the calculation goes on for a day and a night. <br>
       I don't know what's the problem, now I am posting my script and hope anybody could give me some advice. There may be some small error that I cannot recognize. Thank you beforehand.<br><br>Case 1(using uspp):<br>
(1) <a href="http://cnt.in">cnt.in</a><br><br>&CONTROL<br>      calculation = 'relax'<br>      restart_mode='from_scratch',<br>      tstress = .true.<br>      tprnfor = .true.<br>      outdir = '/home/student/espresso-4.3.1/tmp/' ,<br>
      pseudo_dir = '/home/student/espresso-4.3.1/pseudo/' ,<br>      prefix = 'cnt' ,<br> /<br> &SYSTEM<br>                       ibrav = 6,celldm(1) = 21.764541128,celldm(3)=0.213765379<br>                       nat = 24,ntyp = 1,ecutwfc = 35 ,<br>
                     occupations='smearing', smearing='gaussian', degauss=0.02<br> /<br><br> &ELECTRONS<br>                    conv_thr = 1.0d-8 ,<br>                    mixing_beta = 0.7 ,<br> /<br>  &IONS<br>
                 bfgs_ndim         = 3,<br>                 upscale           = 100.D0,<br>                 pot_extrapolation = "second_order",<br>                 wfc_extrapolation = "second_order",<br>
/<br><br>ATOMIC_SPECIES<br>    C   12.01100  C.pz-vbc.UPF <br>    <br>ATOMIC_POSITIONS angstrom<br>  C        4.085165    -0.000000    -1.231010<br>  C        3.838021     1.399343    -1.231010<br>  C        3.537856     2.042582     0.000000<br>
  C        2.624152     3.130877     0.000000<br>  C        2.042582     3.537856    -1.231010<br>  C        0.707144     4.023496    -1.231010<br>  C        0.000000     4.085165     0.000000<br>  C       -1.399343     3.838021     0.000000<br>
  C       -2.042582     3.537856    -1.231010<br>  C       -3.130877     2.624152    -1.231010<br>  C       -3.537856     2.042582     0.000000<br>  C       -4.023496     0.707144     0.000000<br>  C       -4.085165     0.000000    -1.231010<br>
  C       -3.838021    -1.399343    -1.231010<br>  C       -3.537856    -2.042582     0.000000<br>  C       -2.624152    -3.130877     0.000000<br>  C       -2.042582    -3.537856    -1.231010<br>  C       -0.707144    -4.023496    -1.231010<br>
  C       -0.000000    -4.085165     0.000000<br>  C        1.399343    -3.838021     0.000000<br>  C        2.042582    -3.537856    -1.231010<br>  C        3.130877    -2.624152    -1.231010<br>  C        3.537856    -2.042582     0.000000<br>
  C        4.023496    -0.707144     0.000000<br>    <br><br>K_POINTS automatic <br>    1 1 5 0 0 0<br><br>(2) <a href="http://cucnt.in">cucnt.in</a><br><br>&CONTROL<br>      calculation = 'relax'<br>      restart_mode='from_scratch',<br>
      tstress = .true.<br>      tprnfor = .true.<br>      outdir = '/home/student/espresso-4.3.1/tmp/' ,<br>      pseudo_dir = '/home/student/espresso-4.3.1/pseudo/' ,<br>      prefix = 'cntcu' ,<br>
 /<br><br> &SYSTEM<br>                       ibrav = 6,celldm(1) = 21.764541128,celldm(3)=0.213765379<br>                       nat = 25,ntyp = 2,ecutwfc = 35 ,<br>                     occupations='smearing', smearing='gaussian', degauss=0.02<br>
 /<br><br> &ELECTRONS<br>                    conv_thr = 1.0d-8 ,<br>                    mixing_beta = 0.7 ,<br> /<br> &IONS<br>                 bfgs_ndim         = 3,<br>                 upscale           = 100.D0,<br>
                 pot_extrapolation = "second_order",<br>                 wfc_extrapolation = "second_order",<br>/<br>ATOMIC_SPECIES<br>    C   12.01100  C.pz-vbc.UPF <br>    Cu  63.55     Cu.pz-d-rrkjus.UPF<br>
    <br>ATOMIC_POSITIONS angstrom<br>  C        4.085165    -0.000000    -1.231010<br>  C        3.838021     1.399343    -1.231010<br>  C        3.537856     2.042582     0.000000<br>  C        2.624152     3.130877     0.000000<br>
  C        2.042582     3.537856    -1.231010<br>  C        0.707144     4.023496    -1.231010<br>  C        0.000000     4.085165     0.000000<br>  C       -1.399343     3.838021     0.000000<br>  C       -2.042582     3.537856    -1.231010<br>
  C       -3.130877     2.624152    -1.231010<br>  C       -3.537856     2.042582     0.000000<br>  C       -4.023496     0.707144     0.000000<br>  C       -4.085165     0.000000    -1.231010<br>  C       -3.838021    -1.399343    -1.231010<br>
  C       -3.537856    -2.042582     0.000000<br>  C       -2.624152    -3.130877     0.000000<br>  C       -2.042582    -3.537856    -1.231010<br>  C       -0.707144    -4.023496    -1.231010<br>  C       -0.000000    -4.085165     0.000000<br>
  C        1.399343    -3.838021     0.000000<br>  C        2.042582    -3.537856    -1.231010<br>  C        3.130877    -2.624152    -1.231010<br>  C        3.537856    -2.042582     0.000000<br>  C        4.023496    -0.707144     0.000000<br>
  Cu       0            0            0<br>   <br>K_POINTS automatic <br>    1 1 5 0 0 0<br><br><br>(3) <a href="http://cu.in">cu.in</a><br><br>&CONTROL            <br>                calculation='scf',<br>                restart_mode='from_scratch',<br>
                outdir = '/home/student/espresso-4.3.1/tmp/' ,<br>                pseudo_dir = '/home/student/espresso-4.3.1/pseudo/' ,<br>                prefix = 'cu' ,<br> /<br> &SYSTEM<br>                       ibrav = 1,celldm(1)= 20,<br>
                       nat = 1,ntyp = 1,ecutwfc = 35 ,<br>                      occupations='smearing', smearing='gaussian', degauss=0.002<br>                      nspin = 2,<br>                      starting_magnetization(1)=0.2<br>
 /<br><br> &ELECTRONS<br>                    conv_thr = 1.0d-8 ,<br>                    mixing_beta = 0.3 ,<br> /<br><br>ATOMIC_SPECIES<br>  Cu   63.546    Cu.pz-d-rrkjus.UPF<br>    <br>ATOMIC_POSITIONS<br>Cu   0.000000000   0.000000000   0.000000000<br>
<br>K_POINTS GAMMA<br><br>Case 2:(using PAW potential)<br><br>(1)<a href="http://cnt.in">cnt.in</a><br><br>&CONTROL<br>      calculation = 'relax'<br>      restart_mode='from_scratch',<br>      tstress = .true.<br>
      tprnfor = .true.<br>      outdir = '/home/student/espresso-4.3.1/tmp/' ,<br>      pseudo_dir = '/home/student/espresso-4.3.1/pseudo/' ,<br>      prefix = 'cnt' ,<br> /<br> &SYSTEM<br>                       ibrav = 6,celldm(1) = 21.764541128,celldm(3)=0.213765379<br>
                       nat = 24,ntyp = 1,ecutwfc = 50 ,<br>                     occupations='smearing', smearing='gaussian', degauss=0.02<br> /<br><br> &ELECTRONS<br>                    conv_thr = 1.0d-8 ,<br>
                    mixing_beta = 0.7 ,<br> /<br>  &IONS<br>                 bfgs_ndim         = 3,<br>                 upscale           = 100.D0,<br>                 pot_extrapolation = "second_order",<br>
                 wfc_extrapolation = "second_order",<br>/<br><br>ATOMIC_SPECIES<br>    C   12.01100  C.pbe-mt_gipaw.UPF<br>    <br>ATOMIC_POSITIONS angstrom<br>  C        4.085165    -0.000000    -1.231010<br>  C        3.838021     1.399343    -1.231010<br>
  C        3.537856     2.042582     0.000000<br>  C        2.624152     3.130877     0.000000<br>  C        2.042582     3.537856    -1.231010<br>  C        0.707144     4.023496    -1.231010<br>  C        0.000000     4.085165     0.000000<br>
  C       -1.399343     3.838021     0.000000<br>  C       -2.042582     3.537856    -1.231010<br>  C       -3.130877     2.624152    -1.231010<br>  C       -3.537856     2.042582     0.000000<br>  C       -4.023496     0.707144     0.000000<br>
  C       -4.085165     0.000000    -1.231010<br>  C       -3.838021    -1.399343    -1.231010<br>  C       -3.537856    -2.042582     0.000000<br>  C       -2.624152    -3.130877     0.000000<br>  C       -2.042582    -3.537856    -1.231010<br>
  C       -0.707144    -4.023496    -1.231010<br>  C       -0.000000    -4.085165     0.000000<br>  C        1.399343    -3.838021     0.000000<br>  C        2.042582    -3.537856    -1.231010<br>  C        3.130877    -2.624152    -1.231010<br>
  C        3.537856    -2.042582     0.000000<br>  C        4.023496    -0.707144     0.000000<br>    <br><br>K_POINTS automatic <br>    1 1 5 0 0 0<br><br>(2) <a href="http://cucnt.in">cucnt.in</a><br><br>&CONTROL<br>
      calculation = 'relax'<br>      restart_mode='from_scratch',<br>      tstress = .true.<br>      tprnfor = .true.<br>      outdir = '/home/student/espresso-4.3.1/tmp/' ,<br>      pseudo_dir = '/home/student/espresso-4.3.1/pseudo/' ,<br>
      prefix = 'cntcu' ,<br> /<br><br> &SYSTEM<br>                       ibrav = 6,celldm(1) = 21.764541128,celldm(3)=0.213765379<br>                       nat = 25,ntyp = 2,ecutwfc = 50 ,<br>                     occupations='smearing', smearing='gaussian', degauss=0.02<br>
 /<br><br> &ELECTRONS<br>                    conv_thr = 1.0d-8 ,<br>                    mixing_beta = 0.7 ,<br> /<br> &IONS<br>                 bfgs_ndim         = 3,<br>                 upscale           = 100.D0,<br>
                 pot_extrapolation = "second_order",<br>                 wfc_extrapolation = "second_order",<br>/<br>ATOMIC_SPECIES<br>    C   12.01100  C.pbe-mt_gipaw.UPF<br>    Cu  63.55     Cu.pbe-paw_kj.UPF<br>
    <br>ATOMIC_POSITIONS angstrom<br>  C        4.085165    -0.000000    -1.231010<br>  C        3.838021     1.399343    -1.231010<br>  C        3.537856     2.042582     0.000000<br>  C        2.624152     3.130877     0.000000<br>
  C        2.042582     3.537856    -1.231010<br>  C        0.707144     4.023496    -1.231010<br>  C        0.000000     4.085165     0.000000<br>  C       -1.399343     3.838021     0.000000<br>  C       -2.042582     3.537856    -1.231010<br>
  C       -3.130877     2.624152    -1.231010<br>  C       -3.537856     2.042582     0.000000<br>  C       -4.023496     0.707144     0.000000<br>  C       -4.085165     0.000000    -1.231010<br>  C       -3.838021    -1.399343    -1.231010<br>
  C       -3.537856    -2.042582     0.000000<br>  C       -2.624152    -3.130877     0.000000<br>  C       -2.042582    -3.537856    -1.231010<br>  C       -0.707144    -4.023496    -1.231010<br>  C       -0.000000    -4.085165     0.000000<br>
  C        1.399343    -3.838021     0.000000<br>  C        2.042582    -3.537856    -1.231010<br>  C        3.130877    -2.624152    -1.231010<br>  C        3.537856    -2.042582     0.000000<br>  C        4.023496    -0.707144     0.000000<br>
  Cu       0            0            0<br>   <br>K_POINTS automatic <br>    1 1 5 0 0 0<br><br><br>(3) <a href="http://cu.in">cu.in</a> <br> <br><br>&CONTROL            <br>                calculation='scf',<br>
                restart_mode='from_scratch',<br>                outdir = '/home/student/espresso-4.3.1/tmp/' ,<br>                pseudo_dir = '/home/student/espresso-4.3.1/pseudo/' ,<br>                prefix = 'cu' ,<br>
 /<br> &SYSTEM<br>                       ibrav = 1,celldm(1)= 20,<br>                       nat = 1,ntyp = 1,ecutwfc = 50 ,<br>                      occupations='smearing', smearing='gaussian', degauss=0.002<br>
                      nspin = 2,<br>                      starting_magnetization(1)=0.2<br> /<br><br> &ELECTRONS<br>                    conv_thr = 1.0d-8 ,<br>                    mixing_beta = 0.3 ,<br> /<br><br>ATOMIC_SPECIES<br>
  Cu   63.546     Cu.pbe-paw_kj.UPF<br>    <br>ATOMIC_POSITIONS<br>Cu   0.000000000   0.000000000   0.000000000<br><br>K_POINTS GAMMA<br><br><br><br><br>University of Central Florida<br>MMAE<br>Chengyu Yang<br><br><br>