Dear All,<br>     I have a question about this input file in example03.<br>cat > <a href="http://al001.mm.in">al001.mm.in</a> << EOF<br>&CONTROL<br>  calculation = "relax",<br> <b> dt          = 30.D0,</b><br>
  pseudo_dir  = "$PSEUDO_DIR",<br>  outdir      = "$TMP_DIR",<br>/<br>&SYSTEM<br>  ibrav       = 6,<br>  celldm(1)   = 5.3033D0,<br>  celldm(3)   = 8.D0,<br>  nat         = 7,<br>  ntyp        = 1,<br>
  ecutwfc     = 12.D0,<br>  occupations = "smearing",<br>  smearing    = "methfessel-paxton",<br>  degauss     = 0.05D0,<br>/<br>&ELECTRONS<br>  conv_thr    = 1.D-7,<br>  mixing_beta = 0.3D0,<br>/<br>
&IONS<br><b>  ion_dynamics      = "damp",</b><br>  pot_extrapolation = "second_order",<br>  wfc_extrapolation = "second_order",<br>/<br><br>Is the "dt" necessory for the "ion_dynamics=damp" ? And how to determine the value of "dt"?<br>
<br>Thanks.<br>