<div dir="ltr">Hey <span itemprop="author" itemscope="" itemtype="http://schema.org/Person" style="color:rgb(102,102,102);text-decoration:none;font-family:helvetica,arial,sans-serif;font-size:13px;line-height:18.2px"><span itemprop="name"><a href="http://www.mail-archive.com/search?l=pw_forum@pwscf.org&q=from:%22Paolo+Giannozzi%22" rel="nofollow" style="color:rgb(102,102,102);text-decoration:none;font-family:helvetica,arial,sans-serif;font-size:13px;line-height:18.2px">Paolo</a>,</span></span><div><span itemprop="author" itemscope="" itemtype="http://schema.org/Person" style="color:rgb(102,102,102);text-decoration:none;font-family:helvetica,arial,sans-serif;font-size:13px;line-height:18.2px"><span itemprop="name"><br></span></span></div><div><font color="#666666" face="helvetica, arial, sans-serif"><span style="line-height:18.2px">The reason I chose such a ridiculously high screening parameter was to see the difference between my highest occupied and lowest unoccupied states. I was finding that regardless of whether the screening parameter was 0.0 all the way to 100, I'm getting the same band gap for silicon (0.61 eV). </span></font></div><div><font color="#666666" face="helvetica, arial, sans-serif"><span style="line-height:18.2px"><br></span></font></div><div><font color="#666666" face="helvetica, arial, sans-serif"><span style="line-height:18.2px">Thanks,</span></font></div><div><font color="#666666" face="helvetica, arial, sans-serif"><span style="line-height:18.2px"><br></span></font></div><div><font color="#666666" face="helvetica, arial, sans-serif"><span style="line-height:18.2px">Phil</span></font></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 5 November 2015 at 09:02, Ref Fymz <span dir="ltr"><<a href="mailto:reffymz@gmail.com" target="_blank">reffymz@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear pw_forum,<div><br></div><div><br></div><div>I am trying to use the HSE hybrid functional within quantum espresso, I have an 8 atom cubic silicon cell, and I have converged my k-point grid, q-point grid, and my wavefunction ecut. However, regardless of how much I change my screening parameter (from 0.0 bohr^-1 all the way to 100 bohr^-1), the difference between my lowest unoccupied and highest occupied state remains about 0.61 eV, this points towards a problem. Can anybody point me in the right direction?</div><div><br></div><div>Also, when I do an scf run, I'm not getting the pressures / forces printed in the file, despite asking for them, is this due to the density of my k-point and q-point grid?</div><div><br></div><div>The only other thing I can think it could be from is the ecutvcut / x_gamma_extrapolation / exxdiv_treatment. Has anybody else used QE for silicon successfully? </div><div><br></div><div>My input looks like this;</div><div><br></div><div><div> &control</div><div> prefix='silicon',</div><div> pseudo_dir = 'espresso/pseudo/',</div><div> outdir='./tmp'</div><div> tprnfor = .true.</div><div> tstress = .true.</div><div> restart_mode = 'from_scratch'</div><div><br></div><div> /</div><div> &system</div><div> ibrav = 1, celldm(1) =10.327, nat= 8, ntyp= 1,</div><div> ecutwfc = 120, input_dft = 'hse'</div><div> nqx1 = 8, nqx2 = 8, nqx3 = 8</div><div> nbnd = 32</div><div> screening_parameter = 100</div><div> occupations = 'fixed'</div><div> /</div><div> &electrons</div><div> diagonalization='cg'</div><div> conv_thr = 1.0e-9</div><div> /</div><div>ATOMIC_SPECIES</div><div> Si 28.086 Si.pbe-mt_fhi.UPF</div><div><br></div><div>ATOMIC_POSITIONS alat</div><div> Si 0.0 0.0 0.0</div><div> Si 0.5 0.5 0.0</div><div> Si 0.5 0.0 0.5</div><div> Si 0.0 0.5 0.5</div><div> Si 0.25 0.25 0.25</div><div> Si 0.75 0.75 0.25</div><div> Si 0.75 0.25 0.75</div><div> Si 0.25 0.75 0.75</div><div><br></div><div>K_POINTS automatic</div><div>24 24 24 0 0 0</div></div><div><br></div><div><br></div><div><br></div><div>Thanks,</div><div><br></div><div><br></div><div>Phil</div></div>
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