<div dir="ltr">Dear Regina, Pt have a FCC crystal structure, so if you are studing Pt(111) surface, you need 3 layer to have 1 slab, i.e. to describe the Pt(111) surface in general you should use 3, 6, 9 or 12, .etc.. layers. In the case of Pt(100) surface are 2, 4, 6,.. layers. May be this is the reason that your calculation does not converge.<div><br></div><div>Best</div><div><br></div><div>Dr. Arles V. Gil Rebaza</div><div>Instituto de Física La Plata</div><div>La Plata - Argentina</div></div><div class="gmail_extra"><br><div class="gmail_quote">2016-07-20 10:34 GMT-03:00 Regina Lelis de Sousa <span dir="ltr"><<a href="mailto:rlsousa@mail.uft.edu.br" target="_blank">rlsousa@mail.uft.edu.br</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear all,<br>I am studying Pt(111) and Pt(100) surfaces (using a slab model) with PWSCF. I ran a structural relaxations for slabs containing 4 - 9 atomic planes (layers) and everything was fine. In all calculations a vacuum region of the order of 15 Angstroms was  used. However, in the calculations with 10 atomic planes or more the SCF procedure does not converge and i do not understand the reason. I did some changes on SCF procedure (for example: I tested cg method among other things). Does anyone notice some mistake with the input file or with my atomic coordinates?  Any help would be appreciated.<br><br><br> The  inputs and outputs are:<br><br>1 - First Try:<br>$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$<br>&control<br>    calculation = 'relax'<br>    restart_mode='from_scratch',<br>    prefix='Pt_100_12_layers_15_vacuo',<br>    tprnfor = .true.,<br>    tstress =.true.,<br>    verbosity ='high',<br>    pseudo_dir = '/home/rlsousa/Pseudopot',<br> /<br> &system<br>    ibrav=  6,<br>A = 2.831157456,<br>C=37.2,<br>    nat=  12,<br>    ntyp= 1,<br>    ecutwfc =35.0,<br>    ecutrho = 350.0,<br>    occupations='smearing',<br>    smearing='marzari-vanderbilt',<br>    degauss=0.01, !I tested this.<br> /<br> &electrons<br>    mixing_beta = 0.7,<br>    conv_thr =  1.0d-8<br>electron_maxstep = 600,<br> /<br>&ions<br>/<br>ATOMIC_SPECIES<br>Pt  195.084 Pt.pbe-nd-rrkjus.UPF<br>ATOMIC_POSITIONS {angstrom}<br>Pt    0.000000    0.000000    0.000000<br>Pt    1.414214    1.414214    2.000000<br>Pt    0.000000    0.000000    4.000000<br>Pt    1.414214    1.414214    6.000000<br>Pt    0.000000    0.000000    8.000000<br>Pt    1.414214    1.414214    10.000000<br>Pt    0.000000    0.000000    12.000000<br>Pt    1.414214    1.414214    14.000000<br>Pt    0.000000    0.000000    16.000000<br>Pt    1.414214    1.414214    18.000000<br>Pt    0.000000    0.000000    20.000000<br>Pt    1.414214    1.414214    22.000000<br>K_POINTS AUTOMATIC<br>16 16 1 1 1 1<br>$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$<br>OUTPUT:<br><br>     Program PWSCF v.5.0.1 starts on  3Mar2016 at  1:58: 2<br>...<br><br>...<br><br>     Self-consistent Calculation<br><br>     iteration #  1     ecut=    35.00 Ry     beta=0.70<br>     Davidson diagonalization with overlap<br>     ethr =  1.00E-02,  avg # of iterations =  4.0<br><br>     total cpu time spent up to now is      212.7 secs<br><br>     total energy              =   -1037.38592080 Ry<br>     Harris-Foulkes estimate   =   -1039.73360971 Ry<br>     estimated scf accuracy    <       2.83017780 Ry<br><br>     iteration #  2     ecut=    35.00 Ry     beta=0.70<br>     Davidson diagonalization with overlap<br>     ethr =  2.36E-03,  avg # of iterations =  8.9<br><br>     total cpu time spent up to now is      627.5 secs<br><br>     total energy              =   -1004.47885510 Ry<br>     Harris-Foulkes estimate   =   -1113.67210149 Ry<br>     estimated scf accuracy    <    4035.50057863 <br><br>...<br><br><br>     iteration #600     ecut=    35.00 Ry     beta=0.70<br>     Davidson diagonalization with overlap<br>     ethr =  2.92E-05,  avg # of iterations = 11.5<br><br>     total cpu time spent up to now is   250301.6 secs<br><br>     total energy              =   -1025.14170975 Ry<br>     Harris-Foulkes estimate   =   -1050.93732899 Ry<br>     estimated scf accuracy    <     312.87625423 Ry<br><br>     End of self-consistent calculation<br><br>     convergence NOT achieved after 600 iterations: stopping<br><br><br>===================================================================================<br>=   BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES<br>=   EXIT CODE: 1<br>=   CLEANING UP REMAINING PROCESSES<br>=   YOU CAN IGNORE THE BELOW CLEANUP MESSAGES<br>===================================================================================<br><br>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>2 - Second Try:<br>I did:<br> &electrons<br>diagonalization='cg'<br>    mixing_beta = 0.5,<br>    conv_thr =  1.0d-8<br>electron_maxstep = 300,<br><br>and this work fine only for Pt(100) with 10 atomic plane.<br><br>$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$<br>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>3 - Third Try:<br>For Pt(111) with 10 atomic planes:<br>$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$<br> &control<br>    calculation = 'relax'<br>    restart_mode='from_scratch',<br>    prefix='Pt_111_10_layers',<br>    tprnfor = .true.,<br>    tstress =.true.,<br>    verbosity ='high',<br>    pseudo_dir = '/home/rlsousa/pseudo/'<br> /<br> &system<br>    ibrav=  4,<br>A = 2.831157456,<br>C=36.0,<br>    nat=  10,<br>    ntyp= 1,<br>    ecutwfc =35.0,<br>    ecutrho = 350.0,<br>    occupations='smearing',<br>    smearing='marzari-vanderbilt',<br>    degauss=0.01,<br> /<br> &electrons<br>    mixing_beta = 0.7,<br>    conv_thr =  1.0d-8<br>electron_maxstep = 600,<br> /<br>&ions<br>/<br>ATOMIC_SPECIES<br>Pt  195.084 Pt.pbe-nd-rrkjus.UPF<br>ATOMIC_POSITIONS {angstrom}<br>Pt -0.000000000 -0.000000000 -20.784609691<br>Pt 0.000000000 -0.000000000 -13.856406461<br>Pt 0.000000000 -0.000000000 -6.928203230<br>Pt 0.000000000 0.000000000 0.000000000<br>Pt 1.414213562 0.816496581 -16.165807537<br>Pt 1.414213562 0.816496581 -9.237604307<br>Pt 1.414213562 0.816496581 -2.309401077<br>Pt -0.000000000 1.632993162 -18.475208614<br>Pt -0.000000000 1.632993162 -11.547005384<br>Pt -0.000000000 1.632993162 -4.618802154<br>K_POINTS AUTOMATIC<br>16 16 1 1 1 1<br>$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$<br>And the output is:<br>$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$<br>     Self-consistent Calculation<br><br>     iteration #  1     ecut=    35.00 Ry     beta=0.70<br>     Davidson diagonalization with overlap<br>     ethr =  1.00E-02,  avg # of iterations =  3.7<br><br>     total cpu time spent up to now is      619.8 secs<br><br>     total energy              =    -864.90667968 Ry<br>     Harris-Foulkes estimate   =    -866.46381391 Ry<br>     estimated scf accuracy    <       1.92161923 Ry<br><br>     iteration #  2     ecut=    35.00 Ry     beta=0.70<br>     Davidson diagonalization with overlap<br>     ethr =  1.92E-03,  avg # of iterations =  8.8<br><br>     total cpu time spent up to now is     1789.4 secs<br><br>     total energy              =    -834.69092069 Ry<br>     Harris-Foulkes estimate   =    -912.73406647 Ry<br>     estimated scf accuracy    <    3297.67106012 Ry<br>    iteration #154     ecut=    35.00 Ry     beta=0.70<br>     Davidson diagonalization with overlap<br>     ethr =  8.37E-05,  avg # of iterations =  7.2<br><br>     negative rho (up, down):  0.577E-07 0.000E+00<br><br>     total cpu time spent up to now is   143089.7 secs<br><br>     total energy              =    -862.54326840 Ry<br>     Harris-Foulkes estimate   =    -876.81955048 Ry<br>     estimated scf accuracy    <     354.34333068 Ry<br><br>     iteration #155     ecut=    35.00 Ry     beta=0.70<br>     Davidson diagonalization with overlap<br>$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$<br><br>4 - fourth Try:<br>The atomic positions for input file was optimized with a PCFF force field:<br>a - For Pt(100) with 16 atomic planes, the atomic positions for input were:<br>Pt 0.000001863 -0.000006550 1.917081940<br>Pt -0.000000583 -0.000002969 5.858730954<br>Pt -0.000001806 0.000000728 9.775507899<br>Pt -0.000003453 0.000006845 13.688807549<br>Pt -0.000001863 0.000006007 17.601709335<br>Pt -0.000000324 0.000000339 21.516053222<br>Pt 0.000003440 -0.000003229 25.439026038<br>Pt 0.000005016 -0.000002994 29.455726011<br>Pt 1.382821195 1.382814326 -0.121704445<br>Pt 1.382818575 1.382816058 3.895001445<br>Pt 1.382817093 1.382818978 7.817973036<br>Pt 1.382816565 1.382824166 11.732314256<br>Pt 1.382814960 1.382827050 15.645213637<br>Pt 1.382818406 1.382822391 19.558517247<br>Pt 1.382820459 1.382816862 23.475296312<br>Pt 1.382823964 1.382815499 27.416943612<br><br>But I get the same result.<br>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>5 - fifth try - I did not have any throuble for these cases.<br>a - For Pt(100) with 9 atomic planes:<br>$$$$$$$$$$$$$$$$$$$$$$$$$$$<br>.....<br> &system<br>    ibrav=  6,<br>A = 2.831157456,<br>C=33.2,<br>    nat=  9,<br>    ntyp= 1,<br>    ecutwfc =35.0,<br>    ecutrho = 350.0,<br>    occupations='smearing',<br>    smearing='marzari-vanderbilt',<br>    degauss=0.01,<br> /<br> &electrons<br>diagonalization='cg'<br>    mixing_beta = 0.5,<br>    conv_thr =  1.0d-8<br>electron_maxstep = 300,<br> /<br>&ions<br>/<br>ATOMIC_SPECIES<br>Pt  195.084 Pt.pbe-nd-rrkjus.UPF<br>ATOMIC_POSITIONS {angstrom}<br>Pt 0.000000000 -0.000000000 2.001930636<br>Pt 0.000000000 -0.000000000 6.005791907<br>Pt 0.000000000 -0.000000000 10.009653178<br>Pt 0.000000000 -0.000000000 14.013514450<br>Pt 1.415578728 1.415578728 -0.000000000<br>Pt 1.415578728 1.415578728 4.003861271<br>Pt 1.415578728 1.415578728 8.007722543<br>Pt 1.415578728 1.415578728 12.011583814<br>Pt 1.415578728 1.415578728 16.015445086<br><br>.....<br>$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$<br><br>Atomic positions for Pt(100) with 9 atomic planes:<br>$$$$$$$$$$$$$$$$$$$$$$$$$$$<br>b - For Pt(111) with 9 atomic planes:<br> &system<br>    ibrav=  4,<br>A = 2.831157456,<br>C=36.0,<br>    nat=  9,<br>    ntyp= 1,<br>    ecutwfc =35.0,<br>    ecutrho = 350.0,<br>    occupations='smearing',<br>    smearing='marzari-vanderbilt',<br>    degauss=0.01,<br> /<br> &electrons<br>    mixing_beta = 0.7,<br>    conv_thr =  1.0d-8<br>electron_maxstep = 600,<br> /<br>&ions<br>/<br>ATOMIC_SPECIES<br>Pt  195.084 Pt.pbe-nd-rrkjus.UPF<br>ATOMIC_POSITIONS {angstrom}<br>Pt 0.000000000 -0.000000000 -13.856406461<br>Pt 0.000000000 -0.000000000 -6.928203230<br>Pt 0.000000000 0.000000000 0.000000000<br>Pt 1.414213562 0.816496581 -16.165807537<br>Pt 1.414213562 0.816496581 -9.237604307<br>Pt 1.414213562 0.816496581 -2.309401077<br>Pt -0.000000000 1.632993162 -18.475208614<br>Pt -0.000000000 1.632993162 -11.547005384<br>Pt -0.000000000 1.632993162 -4.618802154<br><br>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br><br>Thanks in advance,<br>regards<br><br>R. Lelis-Sousa.<br>UFT/TO/Brazil.<br><br><br clear="all"><br>-- <br><div data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr">
<span style="font-family:verdana,sans-serif">Tenha uma ótima semana,<br><br>Atenciosamente,<br><br><br>Dra. Regina Lélis de Sousa<br>Professor Adjunto -- Universidade Federal do Tocantins<br>Campus de Araguaína<br>Rua Paraguai SN -- Esquina com a Urixamas<br>Telefone: +55(63)2112-2283<br>Caixa Postal 132<br>CEP: <span>77.838-824</span><br>Tocantins.<br>"Success is knowing that you have done your best and have exploited your<br>God-given or gene-given abilities to the next maximum extent. More than this, no<br>one can do...".  Prof. Alan Graham MacDiarmid<br></span><br></div></div></div></div>
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