<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body dir="auto">
I think that the explanation is in the “many of the orbitals are qualitatively different”. Try to figure out what have in common those which are not. I bet you’ll find a simple rule of thumb … SB<br>
<br>
<div dir="ltr">
<div><span style="background-color: rgba(255, 255, 255, 0);">___</span></div>
<div><span style="background-color: rgba(255, 255, 255, 0);">Stefano Baroni, Trieste -- http://stefano.baroni.me</span></div>
</div>
<div dir="ltr"><br>
<blockquote type="cite">On 2 Aug 2022, at 08:46, Phillip Thomas <PThomas@lbl.gov> wrote:<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">
<div dir="ltr">
<div>Dear QE team,</div>
<div><br>
</div>
<div>I have an issue regarding orbitals generated from QE 7.0 runs on two different translated variants of a Silicon lattice. I am using a primitive cubic cell containing 8 atoms instead of the simplest 2-atom unit cell (as I need to pass the output orbitals
to another program which only accepts a tetragonal cell geometry).</div>
<div><br>
</div>
<div>Here is the input file for 'pw.x' for the first variant:</div>
<div>--------------------------------</div>
<div>&control<br>
prefix = 'silicon'<br>
calculation = 'scf'<br>
tstress = .true.<br>
etot_conv_thr = 1d-5<br>
forc_conv_thr = 1d-4<br>
/<br>
&system<br>
ibrav = 1<br>
celldm(1) = 10.173697855629921<br>
nat = 8<br>
ntyp = 1<br>
nbnd = 32<br>
ecutwfc = 80.0<br>
/<br>
&electrons<br>
electron_maxstep = 100<br>
conv_thr = 1.0d-8<br>
mixing_mode = 'plain'<br>
mixing_beta = 0.7<br>
mixing_ndim = 8<br>
diagonalization = 'david'<br>
diago_david_ndim = 4<br>
diago_full_acc = .true.<br>
/<br>
&ions<br>
/<br>
ATOMIC_SPECIES<br>
Si 28.086 Si.pw-mt_fhi.UPF<br>
ATOMIC_POSITIONS alat<br>
Si 0.00 0.00 0.00<br>
Si 0.00 0.50 0.50<br>
Si 0.50 0.00 0.50<br>
Si 0.50 0.50 0.00<br>
Si 0.25 0.25 0.25<br>
Si 0.75 0.75 0.25<br>
Si 0.25 0.75 0.75<br>
Si 0.75 0.25 0.75<br>
K_POINTS automatic<br>
4 4 4 0 0 0</div>
<div>--------------------------------</div>
<div>The second variant has the same input file except that the coordinates of the atoms are shifted to:</div>
<div><br>
</div>
<div> Si 0.125 0.125 0.125<br>
Si 0.125 0.625 0.625<br>
Si 0.625 0.125 0.625<br>
Si 0.625 0.625 0.125<br>
Si 0.375 0.375 0.375<br>
Si 0.875 0.875 0.375<br>
Si 0.375 0.875 0.875<br>
Si 0.875 0.375 0.875<br>
</div>
<div><br>
</div>
<div>Both calculations give the same total energy, -63.52598191 Ry, as I would expect, and the same band structure (except that three additional symmetry equivalent bands are printed out in the latter case); the bands for matching KPOINTS are also the same
in both runs, all as expected. Here are the bands for the 0 0 0 KPOINT for reference:<br>
</div>
<div>--------------------------------</div>
<div> End of self-consistent calculation<br>
<br>
k = 0.0000 0.0000 0.0000 ( 12797 PWs) bands (ev):<br>
<br>
-5.8606 -1.6207 -1.6207 -1.6207 -1.6207 -1.6207 -1.6207 3.3705<br>
3.3706 3.3706 3.3706 3.3706 3.3706 6.2827 6.2827 6.2827<br>
6.8712 6.8712 6.8712 6.8712 6.8712 6.8712 8.8517 8.8517<br>
8.8517 9.6765 14.0241 14.0783 14.0783 16.4618 16.4618 16.4618<br>
</div>
<div>--------------------------------</div>
<div>Now I would like to generate the orbitals for the 0 0 0 KPOINT in cube file format, so here is my input to ''pp.x':</div>
<div>--------------------------------</div>
<div> &inputpp<br>
prefix='silicon'<br>
plot_num=7<br>
kband(1)=1<br>
kband(2)= 32<br>
kpoint=1<br>
lsign=.true.<br>
/<br>
&plot<br>
iflag=3<br>
output_format=6<br>
/</div>
<div>--------------------------------</div>
<div><br>
</div>
<div>When I visually inspect the orbitals, I find that many of the orbitals are qualitatively different for the two translated variants of the lattice; they are not simply translated variants of the same orbital as I would expect. I have attached plots of the
highest occupied orbital (#16) as examples.</div>
<div><br>
</div>
<div>So I am curious, is there a mistake in my inputs or procedure that would cause differences like these? If not, then is there a way in QE that I can generate the orbitals such that they are translationally invariant? Many thanks for looking into this!</div>
<div><br>
</div>
<div>Kind regards,</div>
<div><br>
</div>
<div>Phillip Thomas, Ph.D.<br>
</div>
<div>National Energy Research Scientific Computing Center<br>
</div>
<div>Lawrence Berkeley National Laboratory<br>
</div>
</div>
<img id="f_l6bgwzzw0" alt="orbital16_noshift.png" src="cid:f_l6bgwzzw0"><img id="f_l6bgx0061" alt="orbital16_shifted.png" src="cid:f_l6bgx0061"><span>_______________________________________________</span><br>
<span>The Quantum ESPRESSO community stands by the Ukrainian</span><br>
<span>people and expresses its concerns about the devastating</span><br>
<span>effects that the Russian military offensive has on their</span><br>
<span>country and on the free and peaceful scientific, cultural,</span><br>
<span>and economic cooperation amongst peoples</span><br>
<span>_______________________________________________</span><br>
<span>Quantum ESPRESSO is supported by MaX (www.max-centre.eu)</span><br>
<span>users mailing list users@lists.quantum-espresso.org</span><br>
<span>https://lists.quantum-espresso.org/mailman/listinfo/users</span></div>
</blockquote>
</body>
</html>