<div dir="auto"><div>Dear Sabike,</div><div dir="auto"><br></div><div dir="auto"><div dir="auto">In my experience of working with monolayers, I found that the number of k-points in the k-mesh in z direction aalso affects the convergence. The energy starts converging the moment I increase the number of k-points in z-direction. It also makes sense as you are using two monolayers in your model and thus requires more k-points in the z-direction. </div><div dir="auto"><br></div><div dir="auto">Moreover, you can make the convergence threshold more stringent to about 1e-8 for a proper convergence.</div><div dir="auto"><br></div><div dir="auto">Regards</div><div dir="auto"><div data-smartmail="gmail_signature" dir="auto">Chitta Sai Pavan<br>IIT Gandhinagar</div></div><br><br><div class="gmail_quote" dir="auto"><div dir="ltr">On Tue, 9 Oct 2018, 08:18 Sabike Ghasemi, <<a href="mailto:s.ghasemi@du.ac.ir">s.ghasemi@du.ac.ir</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-family:arial,helvetica,sans-serif;font-size:12pt;color:#000000"><div>dear all<br></div><div>i want to relax atomic coordinates and lattic constants for graphene bilayer. but it dosen't converge.<br></div><div>input file is:<br></div><div><br></div><div><br></div><div> &CONTROL<br>                       title = GRAPHENEBILAYER ,<br>                 calculation = 'vc-relax' ,<br>                restart_mode = 'from_scratch' ,<br>                  wf_collect = .true. ,<br>                      outdir = './out' ,<br>                      wfcdir = './out' ,<br>                  pseudo_dir = './' ,<br>                      prefix = 'GBI' ,<br>                   verbosity = 'high' ,<br>               etot_conv_thr = 1.0D-4 ,<br>               forc_conv_thr = 1.0D-4 ,<br>                     tstress = .true. ,<br>                     tprnfor = .true. ,<br> /<br> &SYSTEM<br>                       ibrav = 4,<br>                   celldm(1) = 4.648726,<br>                   celldm(3) = 9.512195384,<br>                         nat = 4,<br>                        ntyp = 1,<br>                     ecutwfc = 50 ,<br>                     ecutrho = 500 ,<br>                       nosym = .false. ,<br>                 occupations = 'smearing' ,<br>                     degauss = 0.002 ,<br>                    smearing = 'gaussian' ,<br> /<br> &ELECTRONS<br>            electron_maxstep = 200,<br>                    conv_thr = 1.0D-6 ,<br>                 mixing_beta = 0.3 ,<br>             diagonalization = 'david' ,<br> /<br> &IONS<br>                ion_dynamics = 'bfgs' ,<br> /<br> &CELL<br>               cell_dynamics = 'bfgs' ,<br>                 cell_factor = 2.D0 ,<br>                 cell_dofree = '2Dxy' ,<br> /<br>ATOMIC_SPECIES<br>    C   12.00000  C.blyp-mt.UPF <br>ATOMIC_POSITIONS crystal <br>    C      0.333333330    0.666666660    0.572649573    <br>    C      1.000000000    0.000000000    0.572649753    <br>    C      0.666666660    0.333333330    0.427350427    <br>    C      1.000000000    0.000000000    0.427350427    <br>K_POINTS automatic <br>  16 16 1   0 0 0 <br><br></div><div><br></div><div>best, <br></div><div>sabike<br></div></div></div>_______________________________________________<br>
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