Dear Vega,<br> Try reducing "trust_radius_min". I faced the same problem once and I did the same thing and it worked. Normally this happens near the convergence...<br>HAPPY COMPUTING,<br>MOHNISH,<br>
<br><div class="gmail_quote">On Wed, Jan 6, 2010 at 9:11 AM, vega lew <span dir="ltr"><<a href="mailto:quantumdft@gmail.com">quantumdft@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div>Dear all,</div>
<div> </div>
<div>I used to calculate the structure and the energy of Pt dimers (two Pt atoms) in a large supercell. I have tested various structure in triplet, which is most stable state for single Pt atom.</div>
<div>But the code report errors after a few bfgs steps like this: </div>
<div> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br> task # 0<br> from bfgs : error # 1<br> bfgs history already reset at previous step<br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>
</div>
<div>I wondering how to deal with this situation.</div>
<div> </div>
<div>my input files is shown as follows,</div>
<div> &CONTROL <br> calculation = 'relax' , <br>
restart_mode = 'from_scratch' , <br> outdir = '/tmp/' , <br> wfcdir = '/tmp/' , <br>
pseudo_dir = '/home/vega/espresso/pseudo/' , <br> disk_io = 'none' , <br> nstep = 1000 , <br>
/ <br> &SYSTEM <br> ibrav = 8, <br>
celldm(1) =24.8624,<br> celldm(2) = 0.8520,<br> celldm(3) = 1.6964,<br> nat = 2, <br> ntyp = 1, <br>
nosym = .true. , <br> ecutwfc = 30,<br> ecutrho = 300,<br> occupations = 'smearing',<br>
degauss = 0.007,<br> nspin = 2,<br> multiplicity = 3,<br> / <br> &ELECTRONS <br>
mixing_mode ='local-TF',<br> mixing_beta = 0.4, <br> <br> / <br>
&IONS <br> ion_dynamics = 'bfgs' , <br> / <br>
ATOMIC_SPECIES <br> Pt 195.08 Pt.pw91-n-van.UPF <br>ATOMIC_POSITIONS crystal <br>Pt 0.540794031 0.322983976 0.495002098<br>
Pt 0.500777594 0.548429786 0.493029885<br>K_POINTS gamma</div>
<div> </div>
<div>the input parameters might not very suitable for the calculation of Pt dimers itself. But the parameters should be consistent with the previous calculation, which is composed of two Pt atoms on certain surface slab model.</div>
<div> </div>
<div>So could any one give me some suggestions? </div>
<div> </div>
<div>Thank you for reading</div>
<div> </div>
<div>vega<br clear="all"><br>-- <br>==================================================================================<br>Vega Lew ( weijia liu)<br>Graduate student<br>State Key Laboratory of Materials-oriented Chemical Engineering<br>
College of Chemistry and Chemical Engineering<br>Nanjing University of Technology, 210009, Nanjing, Jiangsu, China<br>******************************************************************************************************************<br>
Email: <a href="mailto:vegalew@gmail.com" target="_blank">vegalew@gmail.com</a><br>Office: Room A705, Technical Innovation Building, Xinmofan Road 5#, Nanjing, Jiangsu, China <br>****************************************************************************************************************** <br>
</div>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Mohnish Pandey<br>Y6927262,4th Year dual degree student,<br>Department of Chemical Engineering,<br>IIT KANPUR<br>09235721300<br>