<div dir="ltr"><div><div><div>Dear Matthew, </div> If no one else replies... I have serious doubts about your input: The cut-off energy has a historical, (very) low value; you only take one unit cell, and since there are no k points (in your input), you rely on the sampling of the Gamma-point only; what is the electronic structure of this solid, is it possibly metallic, magnetic, strongly-correlated? Maybe the problem is related to one of those issues...? </div> Good Luck and Greetings from Montrouge, </div> apsi </div><div class="gmail_extra"> <div class="gmail_quote">2016-02-02 14:35 GMT+01:00 <<a href="mailto:mj.be...@hotmail.co.uk" target="_blank">mj.be...@hotmail.co.uk</a>>: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear all, I am currently studying solid state compounds using DFT methods with PBE incp2k v2.6. In particular, I am studying the compound SrO. I, however, am having trouble at the first hurdle as I am unable to optimise the structure without massive distortions taking place in the structure. I have also done this for a more simple compound such as SrO but still maintain the same problem. The resulting structure after the calculation has finished heavily distorted and is not in fact optimised. The coordinates used in the input file are those after those of when the atoms repeated by symmetry have been deleted. Here is my input: &FORCE_EVAL METHOD Quickstep &DFT BASIS_SET_FILE_NAME ./BASIS_MOLOPT POTENTIAL_FILE_NAME ./GTH_POTENTIALS &MGRID CUTOFF 280 &END MGRID &QS &END QS &SCF EPS_SCF 1.0E-7 MAX_SCF 500 SCF_GUESS RESTART &OT PRECONDITIONER FULL_ALL MINIMIZER DIIS &END OT &END SCF &POISSON POISSON_SOLVER PERIODIC PERIODIC XYZ &END POISSON &XC &XC_FUNCTIONAL PBE &END XC_FUNCTIONAL &END XC &PRINT &E_DENSITY_CUBE &END &END &END DFT &SUBSYS &CELL ABC 5.161500 5.161500 5.161500 &END CELL &COORD Sr 2.580750 2.580750 2.580750 Sr 2.580750 5.161500 0.000000 Sr 0.000000 2.580750 0.000000 Sr 0.000000 0.000000 2.580750 O 0.000000 0.000000 0.000000 O 0.000000 2.580750 2.580750 O 2.580750 0.000000 2.580750 O 2.580750 2.580750 0.000000 &END COORD &KIND Sr BASIS_SET DZVP-MOLOPT-SR-GTH POTENTIAL GTH-PBE-q10 &END KIND &KIND O BASIS_SET DZVP-MOLOPT-SR-GTH POTENTIAL GTH-PBE-q6 &END KIND &TOPOLOGY &GENERATE BONDLENGTH_MAX 8. &END &END &END SUBSYS &END FORCE_EVAL &GLOBAL PROJECT SrO_GEOPT RUN_TYPE GEO_OPT PRINT_LEVEL MEDIUM PREFERRED_FFT_LIBRARY FFTSG &END GLOBAL &MOTION &GEO_OPT MAX_ITER 300 MAX_FORCE 1.E-5 OPTIMIZER BFGS &END GEO_OPT &END MOTION Here is the coordinates for the resulting geometry of SrO: &CELL A 5.1615000000000002E+00 0.0000000000000000E+00 0.0000000000000000E+00 B 0.0000000000000000E+00 5.1615000000000002E+00 0.0000000000000000E+00 C 0.0000000000000000E+00 0.0000000000000000E+00 5.1615000000000002E+00 MULTIPLE_UNIT_CELL 1 1 1 &END CELL &COORD Sr 1.9890028994522615E+00 2.2193294449078076E+00 2.7910266626701881E+00 Sr 1.9292986629548623E+00 4.8135192380570206E+00 2.1296902553214103E-01 Sr -5.9176277362609420E-01 2.7509938085013901E+00 -3.0581129089048587E-01 Sr -6.5144865196079582E-01 1.5680073585860360E-01 2.2722491342258304E+00 O 4.7898927316432355E-01 8.6395713176665057E-01 -1.0487832154631918E+00 O 4.7694627804364587E-01 3.4395703896268177E+00 1.6198967879945019E+00 O 3.0597429820934190E+00 -1.0551228958752437E+00 3.5339829819921467E+00 O 3.0576968263194555E+00 1.5307475361163412E+00 8.6527187533043926E-01 &END COORD I am really unsure what the problem is and would appreciate any help that people can give me. Many Thanks Matthew Bennett -- You received this message because you are subscribed to the Google Groups "cp2k" group. To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k%2Bun...@googlegroups.com">cp2k+uns...@googlegroups.com</a>. To post to this group, send email to <a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a>. Visit this group at <a href="https://groups.google.com/group/cp2k" rel="noreferrer" target="_blank">https://groups.google.com/group/cp2k</a>. For more options, visit <a href="https://groups.google.com/d/optout" rel="noreferrer" target="_blank">https://groups.google.com/d/optout</a>. </blockquote></div> -- <div class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr">-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=- Ari Paavo Seitsonen / <a href="mailto:Ari.P.S...@iki.fi" target="_blank">Ari.P.S...@iki.fi</a> / <a href="http://www.iki.fi/~apsi/" target="_blank">http://www.iki.fi/~apsi/</a> Ecole Normale Supérieure (ENS), Département de Chimie, Paris Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935 </div></div></div></div></div></div> </div>