<div dir="ltr"><div dir="ltr"><div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)">Thanks all for the reply,</div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"><br>With all the inputs provided here and mail archives, I made some significant changes ( fixed magnetization, increased the size of the cell, Gamma point calculation, Mixing beta etc...).<br><br><b>Input of isolated Ti atom</b>:</div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)">&control<br> calculation = 'scf'<br> restart_mode = 'from_scratch'<br> pseudo_dir = '/work/shared/s-tih/pseudo/'<br> prefix = 'Tifree_deg1_40_gk_1'<br> wf_collect = .true.<br> forc_conv_thr = 1.0d-5<br> verbosity = 'high'<br> /<br>&system<br> ibrav = 1<br> celldm(1) = 30<br> nat = 1<br> ntyp = 1<br> ecutwfc = 40<br> ecutrho = 320<br> nspin = 2<br> tot_magnetization = 2<br> nosym = .true<br> nbnd = 100<br> occupations = 'fixed'<br> /<br>&electrons<br> diagonalization = 'cg'<br> mixing_beta = 0.3d00<br> conv_thr = 1.0d-7<br>/<br>ATOMIC_SPECIES<br> Ti 47.8670 Ti.pbe-spn-rrkjus_psl.1.0.0.UPF<br><br><br>ATOMIC_POSITIONS (crystal)<br> Ti 0.5 0.5 0.5<br><br>K_POINTS GAMMA<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)">And for bulk calculations, i used same forc_conv_thr, ecutwfc, &electrons parameters. <b>But I am still getting 5.23 eV as cohesive energy for Ti</b>. is it possible to get the experimental ( 4.85 eV) using DFT calculations as reported in some of the journals?<br><br>The output of isolated Ti atom calculation looks like,</div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"> bravais-lattice index = 1<br> lattice parameter (alat) = 30.0000 a.u.<br> unit-cell volume = 27000.0000 (a.u.)^3<br> number of atoms/cell = 1<br> number of atomic types = 1<br> number of electrons = 12.00 (up: 7.00, down: 5.00)<br> number of Kohn-Sham states= 100<br> kinetic-energy cutoff = 40.0000 Ry<br> charge density cutoff = 320.0000 Ry<br> convergence threshold = 1.0E-07<br> mixing beta = 0.3000<br> number of iterations used = 8 plain mixing<br> Exchange-correlation = PBE ( 1 4 3 4 0 0)<br><br> celldm(1)= 30.000000 celldm(2)= 0.000000 celldm(3)= 0.000000<br> celldm(4)= 0.000000 celldm(5)= 0.000000 celldm(6)= 0.000000<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)">etc..............................................................................................................</div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"> Starting magnetic structure<br> atomic species magnetization<br> Ti 0.000<br><br> No symmetry found<br>etc..............................................................................................................<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"><div class="gmail_default">..................................................................................................................<br></div><div class="gmail_default"><br></div><div class="gmail_default"></div></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"> iteration # 23 ecut= 40.00 Ry beta= 0.30<br> CG style diagonalization<br> ethr = 1.01E-09, avg # of iterations = 3.1<br><br> negative rho (up, down): 1.660E-02 1.306E-01<br><br> Magnetic moment per site:<br> atom: 1 charge: 11.9999 magn: 2.0000 constr: 0.0000<br><br> total cpu time spent up to now is 108.5 secs<br><br> End of self-consistent calculation<br><br> ------ SPIN UP ------------<br><br> k = 0.0000 0.0000 0.0000 ( 57657 PWs) bands (ev):<br><br> -62.1874 -38.4854 -38.4348 -38.4332 -4.4517 -4.4503 -4.4048 -3.5611<br> -3.5610 -3.5153 -1.4572 -1.4565 -1.1485 -0.4725 0.0828 0.0992<br> 0.1709 0.1890 0.1914 0.2168 0.5306 0.5437 0.6058 0.6689<br> 0.6794 0.6917 0.7097 0.7127 0.8758 0.8811 0.9122 0.9174<br> 1.1513 1.1544 1.1806 1.2368 1.4025 1.4198 1.4417 1.4878<br> 1.5485 1.5709 1.9392 1.9444 1.9629 2.0040 2.0535 2.0683<br> 2.1492 2.1983 2.2084 2.3100 2.3235 2.3454 2.3845 2.4064<br> 2.4189 2.4639 2.4693 2.4865 2.4880 2.5054 2.5055 2.5179<br> 2.5188 2.5215 2.7061 2.7211 2.7420 2.7869 2.7963 2.8090<br> 2.8145 2.8304 2.9938 3.0003 3.0113 3.0175 3.0230 3.0259<br> 3.0280 3.0332 3.0529 3.0580 3.0645 3.0690 3.0757 3.0785<br> 3.0808 3.0898 3.5616 3.5684 3.6347 3.8452 3.9717 3.9774<br> 4.0381 4.0472 4.0540 4.0617<br><br> occupation numbers<br> 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000<br><br> ------ SPIN DOWN ----------<br> k = 0.0000 0.0000 0.0000 ( 57657 PWs) bands (ev):<br><br> -60.5692 -37.0219 -36.7521 -36.7481 -3.9282 -2.9464 -2.8480 -2.8461<br> -2.0737 -2.0734 -1.3881 -0.9733 -0.9724 -0.4455 0.0983 0.1054<br> 0.2139 0.2301 0.2409 0.2476 0.5776 0.5939 0.6083 0.6823<br> 0.6922 0.7172 0.7202 0.7223 0.9007 0.9617 0.9637 0.9653<br> 1.1886 1.2019 1.2109 1.2572 1.4214 1.4579 1.4604 1.5175<br> 1.5802 1.6023 1.9618 1.9874 1.9882 2.0402 2.1348 2.1844<br> 2.2059 2.2275 2.2450 2.3219 2.3301 2.3507 2.4059 2.4124<br> 2.4170 2.4823 2.4877 2.4881 2.5037 2.5077 2.5266 2.5297<br> 2.5305 2.5376 2.7444 2.7669 2.7706 2.8302 2.8379 2.8443<br> 2.8558 2.8670 3.0199 3.0266 3.0335 3.0380 3.0397 3.0427<br> 3.0462 3.0493 3.0781 3.0795 3.0805 3.0813 3.0847 3.0869<br> 3.1009 3.1038 3.6043 3.6940 3.6955 3.9171 4.0363 4.0648<br> 4.0726 4.0791 4.0896 4.0980<br><br> occupation numbers<br> 1.0000 1.0000 1.0000 1.0000 1.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000<br> 0.0000 0.0000 0.0000 0.0000<br><br> highest occupied, lowest unoccupied level (ev): -3.9282 -3.5611<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)">! total energy = -119.34098597 Ry<br> Harris-Foulkes estimate = -119.34098367 Ry<br> estimated scf accuracy < 0.00000010 Ry<br><br> The total energy is the sum of the following terms:<br><br> one-electron contribution = -167.22501663 Ry<br> hartree contribution = 79.78699354 Ry<br> xc contribution = -18.28393498 Ry<br> ewald contribution = -13.61902790 Ry<br><br> total magnetization = 2.00 Bohr mag/cell<br> absolute magnetization = 2.44 Bohr mag/cell<br><br> convergence has been achieved in 23 iterations<br><br><br>Waiting for reply. Thanks for all the inputs.</div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(0,0,0)"><br></div><div><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div style="font-size:12.8px"><span style="font-family:"Times New Roman";font-size:medium">Thanks & Regards,</span><br></div><div style="font-size:12.8px"><b style="font-family:"Times New Roman";font-size:medium">------------------------------------------------------------------------------------------------------</b></div><div style="line-height:22px"><div style="line-height:22px"><font color="#000000" face="arial, helvetica, sans-serif"><span style="font-size:16px">Ajmalghan MUTHALI</span></font></div><div style="line-height:22px"><font color="#000000" face="arial, helvetica, sans-serif"><span style="font-size:16px"><br></span></font></div><div style="line-height:22px"><font color="#000000" face="arial, helvetica, sans-serif"><span style="font-size:16px">Post doctorate researcher</span></font></div><div style="line-height:22px"><font color="#000000" face="arial, helvetica, sans-serif"><span style="font-size:16px">Laboratoire ICB </span></font></div><div style="line-height:22px"><font color="#000000" face="arial, helvetica, sans-serif"><span style="font-size:16px">UMR 6303 CNRS-Université de Bourgogne </span></font></div><div style="line-height:22px"><font color="#000000" face="arial, helvetica, sans-serif"><span style="font-size:16px">9 Avenue Alain Savary, BP 47870 </span></font></div><div style="line-height:22px"><font color="#000000" face="arial, helvetica, sans-serif"><span style="font-size:16px">F-21078 DIJON Cedex, France </span></font></div><div style="line-height:22px"><font color="#000000" face="arial, helvetica, sans-serif"><span style="font-size:16px">Tel: +33-(0)7.69.28.19.91 </span></font></div></div><div style="line-height:22px"><span style="color:rgb(0,0,0);font-family:arial,helvetica,sans-serif;font-size:16px">Email : </span><font color="#000000" face="arial, helvetica, sans-serif"><span style="font-size:16px"><a href="mailto:ajmalghan.muthali@u-bourgogne.fr" target="_blank">ajmalghan.muthali@u-bourgogne.fr</a></span></font></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Nov 10, 2019 at 3:52 PM Ari P Seitsonen <<a href="mailto:Ari.P.Seitsonen@iki.fi">Ari.P.Seitsonen@iki.fi</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
Dear Ajmalghan,<br>
<br>
Some quick comments:<br>
<br>
- Why do you use k point in the case of an isolated atom?? Well, that <br>
should not matter, just that you are wasting computing time<br>
<br>
- I guess that the spherical symmetry of the atom is broken; thus I would <br>
use a non-cube cell, preferably the orthorhombic cell, with slightly <br>
different lengths of the basis vectors of the unit cell. Then to break the <br>
symmetry, you can use some randomisation of the initial wave functions. <br>
And still, the convergence is probably going to be very difficult... You <br>
can indeed try to fix the magnetisation; and I would reduce the <br>
'mixing_beta' to something (very) small - in principle already at the <br>
first step the electron density should be close to the self-consistent <br>
one, bar the loss of sphericality and the randomised wave function<br>
<br>
- Please remember that the scale of 'starting_magnetisation' is from -1 <br>
to +1, meaning that all the electrons are spin-polarised either up or <br>
down, whereas in your case you only want to polarise the two valence <br>
electrons out of the valence of the pseudo potential that seems to be 12 <br>
electrons<br>
<br>
Well, Good Luck. :)<br>
<br>
Greetings from Paris,<br>
<br>
apsi<br>
<br>
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-<br>
Ari Paavo Seitsonen / <a href="mailto:Ari.P.Seitsonen@iki.fi" target="_blank">Ari.P.Seitsonen@iki.fi</a> / <a href="http://www.iki.fi/~apsi/" rel="noreferrer" target="_blank">http://www.iki.fi/~apsi/</a><br>
Ecole Normale Supérieure (ENS), Département de Chimie, Paris<br>
Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935<br>
<br>
<br>
On Sat, 9 Nov 2019, Ajmal Ghan wrote:<br>
<br>
> Hello all,<br>
> <br>
> I have gone through all the archived discussion about cohesive energy calculation.<br>
> <br>
> I am trying to calculate the cohesive energy of Ti which is 4.85eV. But I am getting 5.23 eV which is closer. But I have found from a previous discussion<br>
> here ( <a href="https://www.mail-archive.com/users@lists.quantum-espresso.org/msg11410.html" rel="noreferrer" target="_blank">https://www.mail-archive.com/users@lists.quantum-espresso.org/msg11410.html</a> ) that, the final magnetization should be 2 Bohr mag/ cell at the end<br>
> of calculation for Ti and smearing contribution of energy should be 0.0Ry. <br>
> But I am getting to get 3.83 Bohr mag/cell and a significant smearing contribution = -0.03295688 Ry.<br>
> <br>
> Anyone help me to sort this. what should I change in the input?<br>
> <br>
> <br>
> here is my input,<br>
> <br>
> &control<br>
> calculation = 'scf'<br>
> restart_mode = 'from_scratch'<br>
> pseudo_dir = '/work/shared/s-tih/pseudo/'<br>
> prefix = 'Tifree_deg1_50_8k_1'<br>
> wf_collect = .true.<br>
> tstress = .true.<br>
> tprnfor = .true.<br>
> forc_conv_thr = 1.0d-6<br>
> verbosity = 'high'<br>
> /<br>
> &system<br>
> ibrav = 1<br>
> celldm(1) = 20<br>
> nat = 1<br>
> ntyp = 1<br>
> ecutwfc = 50 //( I have performed convergence study. But since degauss is reduced to 0.01, i increased ecut) <br>
> ecutrho = 400<br>
> nspin = 2<br>
> starting_magnetization(1) = 1 // I think, the final magnetisation should be 2 bohr mag/ cell at the end of calculation.<br>
> nosym = .true /// I hope this is enough to break the symmetry<br>
> nbnd = 100<br>
> occupations = 'smearing', smearing='mp', degauss=0.01D0<br>
> /<br>
> &electrons<br>
> diagonalization = 'cg'<br>
> mixing_beta = 0.7d00<br>
> conv_thr = 1.0d-8 // I used even higher convergence since smearing is reduced.<br>
> /<br>
> ATOMIC_SPECIES<br>
> Ti 47.8670 Ti.pbe-spn-rrkjus_psl.1.0.0.UPF<br>
> <br>
> <br>
> ATOMIC_POSITIONS (crystal)<br>
> Ti 0.5 0.5 0.5<br>
> <br>
> K_POINTS {automatic}<br>
> 8 8 5 0 0 0<br>
> <br>
> <br>
> I don't really know this is the correct way to post a reply. All input is welcome. <br>
> <br>
> Thanks & Regards,<br>
> ------------------------------------------------------------------------------------------------------<br>
> Ajmalghan MUTHALI<br>
> <br>
> Post doctorate researcher<br>
> Laboratoire ICB <br>
> UMR 6303 CNRS-Université de Bourgogne <br>
> 9 Avenue Alain Savary, BP 47870 <br>
> F-21078 DIJON Cedex, France <br>
> Tel: +33-(0)7.69.28.19.91 <br>
> Email : <a href="mailto:ajmalghan.muthali@u-bourgogne.fr" target="_blank">ajmalghan.muthali@u-bourgogne.fr</a><br>
> <br>
>_______________________________________________<br>
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