Hi,<div><br></div><div>You need to figure out numbers of each atomic specie and positions of each atom, ibrav = 2 only gives you three fcc lattice vectors. I don't think it implies fd3m space group.</div><div><br></div>
<div>Bests</div><div>Jia<br><br><div class="gmail_quote">On Mon, Aug 6, 2012 at 10:42 AM, Abolore Musari <span dir="ltr"><<a href="mailto:abmus007@gmail.com" target="_blank">abmus007@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Thanks so much Jia<br>But Sir the atomic positions in the input is for 3 atoms, should l leave the atomic position and change the number of atom or my atomic position is wrong??<br>
thanks<br>Musari A. A<br>UNAAB Nigeria<div class="HOEnZb"><div class="h5"><br>
<br><div class="gmail_quote">On Mon, Aug 6, 2012 at 3:34 PM, jia chen <span dir="ltr"><<a href="mailto:jiachen@princeton.edu" target="_blank">jiachen@princeton.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Dear Abolore Musari,<div><br></div><div>I guess the number of atoms should be 14, instead of 3.</div><div><br></div><div>Regards</div><div>Jia<br><br><div class="gmail_quote"><div><div>On Mon, Aug 6, 2012 at 10:24 AM, Abolore Musari <span dir="ltr"><<a href="mailto:abmus007@gmail.com" target="_blank">abmus007@gmail.com</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div>Dear QE users<br>Sir, I am try to find the lattice constant of magnetite (Fe3O4) which is a spinel ferrimagnetic material. The expt lattice constant was 15.87 and I have been trying to find the equilibrium lattice constant (celldm(1)) between 15.80 - 16.00 and all i get is a straight line graph instead of the usual exponential curve graph. I have tried all l could most esp with starting_magnetization but the results are the same. My input is pasted below pls help me to get the appropriate graph.<br>
The kind of the graph I got is attached.<br>Thanks<br><br>&control<br> calculation = 'scf',<br> restart_mode ='from_scratch',<br> prefix = 'Fe3O4',<br> pseudo_dir = '/home/abolore/Programs/Pseudos/',<br>
outdir = './tmp/'<br> /<br> &system<br> ibrav = 2, <br> celldm(1)= $15.80-16.00,<br> nat = 3, <br> ntyp = 3,<br> ecutwfc = 40,<br> ecutrho = 400,<br> starting_magnetization(1) = 0.7,<br>
starting_magnetization(2) = -0.5,<br> starting_magnetization(3) = 0.0,<br> nspin = 2,<br> occupations='smearing',<br> smearing='gaussian',<br> degauss = 0.05,<br> /<br> &electrons<br>
diagonalization = 'david',<br> mixing_mode = 'plain',<br> mixing_beta = 0.7<br> /<br>ATOMIC_SPECIES<br> Fe1 55.845 Fe.pz-nd-rrkjus.UPF<br> Fe2 55.845 Fe.pz-nd-rrkjus.UPF<br> O 16.000 O.pz-rrkjus.UPF<br>
<br>ATOMIC_POSITIONS<br>Fe1 0.125 0.125 0.125 <br>Fe2 0.500 0.500 0.500<br>O 0.2548 0.2548 0.2548<br> <br>K_POINTS (automatic)<br> 8 8 8 1 1 1<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
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<br></blockquote></div><span><font color="#888888"><br><br clear="all"><div><br></div>-- <br>Jia Chen<br><br><br>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>Jia Chen<br><br>Dept of Chemistry<br>Princeton University<br>Princeton, NJ 08544<br>
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