<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi everyone,<div><br></div><div>I am trying to do a supercell calculation of InAs (zinc blende structure) using the following input file(ibrav=0 and specifying cell parameters with cubic symmetry)</div><div><font class="Apple-style-span" face="Times"><span class="Apple-style-span" style="-webkit-border-horizontal-spacing: 4px; -webkit-border-vertical-spacing: 4px;"><div><br></div><div> &control</div><div> calculation='scf'</div><div> restart_mode='from_scratch',</div><div> tstress = .true.</div><div> tprnfor = .true.</div><div> prefix='inas',</div><div> pseudo_dir = '/home/ba01/u110/singh36/espresso-4.1.3/pseudo/',</div><div> outdir='./tmp'</div><div> /</div><div> &system</div><div> ibrav=0,</div><div> celldm(1)=11.05,</div><div> nat= 8,</div><div> ntyp= 2,</div><div> ecutwfc =25.0</div><div> ecutrho=250.0</div><div> /</div><div> &electrons</div><div> conv_thr = 1.0d-8</div><div> mixing_beta = 0.7</div><div> /</div><div>ATOMIC_SPECIES</div><div> In 114.818 In.pz-bhs.UPF</div><div> As 74.921 As.pz-bhs.UPF</div><div>CELL PARAMETERS{cubic}</div><div> 1.0 0.0 0.0</div><div> 0.0 1.0 0.0</div><div> 0.0 0.0 1.0</div><div><br></div><div>ATOMIC_POSITIONS {crystal}</div><div> In 0.00 0.00 0.00</div><div> As 0.25 0.25 0.25</div><div> In 0.50 0.50 0.00</div><div> As 0.75 0.75 0.25</div><div> In 0.00 0.50 0.50</div><div> As 0.25 0.75 0.75</div><div> In 0.50 0.00 0.50</div><div> As 0.75 0.25 0.75</div><div>K_POINTS {automatic}</div><div> 4 4 4 0 0 0</div><div><br></div><div>Strangely enough an scf run does not read the cell parameters card and I get an error</div><div><br></div><div><div> Waiting for input...</div><div>Warning: card CELL PARAMETERS{CUBIC} ignored</div><div>Warning: card 1.0 0.0 0.0 ignored</div><div>Warning: card 0.0 1.0 0.0 ignored</div><div>Warning: card 0.0 0.0 1.0 ignored</div><div><br></div><div> %%%%%%%%%%%%%%%%%%%%%%%%%</div><div> from read_cards : error # 1</div><div> ibrav=0: must read cell parameters</div><div> %%%%%%%%%%%%%%%%%%%%%%%%%</div><div><br></div><div> stopping ...</div><div><br></div></div></span></font></div><div>--------</div><div><br></div><div>I have run a few calculations in the past with the cubic supercell specifying different values of cell parameters and they work fine. Also the calculation runs fine with ibrav=1 (and not specifying the cell parameters). However, I am not able to pin down the mistake I am making here (Are we not allowed to specify a free lattice if it has equal cell parameters?).</div><div><br></div><div>Thanks,</div><div>Dhruv Singh</div><div>School of Mechanical Engineering, Purdue University</div></body></html>