Dear Alessandro, After a quick look at your input, the following line (marked in bold) seem to be erroneous: ---------------------------------- &CELL ABC 7.552 7.552 11.328 18.972 ALPHA_BETA_GAMMA 90.0 90.0 90.0 PERIODIC XYZ &END CELL ---------------------------------- From your geometry, I think the correct cell parameters should be: ABC 7.552 7.552 18.972 Could you re-check your original input file and see if the problem still exists after this correction? Best regards, Irene <div class="gmail_quote">On Thu, Dec 1, 2011 at 9:34 AM, <a href="mailto:motta...@hotmail.com">motta...@hotmail.com</a> <<a href="mailto:motta...@hotmail.com">motta...@hotmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Hi I am a newby of this group. My probles is the follow: I am trying to perform a cell optimization of an TiO2 anatase structure, but somewhat does not work. In fact after tree or four cell cycles the cell expands to much and the geometry optimization lead to an unrealistic structure too far from the anatase experimental structure and sine this trend I decide to stop the run. I started with a 2x2x2 unit cell of anatase (96 atoms) as the following input declares: #&EXT_RESTART # RESTART_FILE_NAME ./tio2_anatase2x2-GEO_OPT-2-1.restart # RESTART_COUNTERS F # RESTART_POS T # RESTART_VEL F # RESTART_THERMOSTAT T # RESTART_CONSTRAINT F # RESTART_CELL F # RESTART_BAROSTAT F #&END EXT_RESTART &GLOBAL PROJECT tio2_2x2x2 RUN_TYPE CELL_OPT PRINT_LEVEL LOW &END GLOBAL &FORCE_EVAL METHOD QS &DFT BASIS_SET_FILE_NAME ../BASIS_MOLOPT POTENTIAL_FILE_NAME ../GTH_POTENTIALS CHARGE 0 &MGRID CUTOFF 400 NGRIDS 5 &END MGRID &QS METHOD GPW &END QS # WFN_RESTART_FILE_NAME ./tio2_anatase2x2-GEO_OPT-2-RESTART.wfn &SCF MAX_SCF 40 EPS_SCF 1.0E-6 CHOLESKY OFF SCF_GUESS ATOMIC &OT MINIMIZER CG PRECONDITIONER FULL_SINGLE_INVERSE &END OT &OUTER_SCF EPS_SCF 1.0E-6 MAX_SCF 10 &END OUTER_SCF &PRINT &RESTART &END &RESTART_HISTORY &END &END PRINT &END SCF &XC &XC_FUNCTIONAL PBE &END XC_FUNCTIONAL &VDW_POTENTIAL POTENTIAL_TYPE PAIR_POTENTIAL &PAIR_POTENTIAL REFERENCE_FUNCTIONAL PBE PARAMETER_FILE_NAME ../dftd3.dat TYPE DFTD3 R_CUTOFF [angstrom] 30 &END PAIR_POTENTIAL &END VDW_POTENTIAL &END XC &END DFT &SUBSYS &CELL ABC 7.552 7.552 11.328 18.972 ALPHA_BETA_GAMMA 90.0 90.0 90.0 PERIODIC XYZ &END CELL &TOPOLOGY COORDINATE XYZ COORD_FILE_NAME ./tio2_2x2x2_ini.xyz CONNECTIVITY OFF &END TOPOLOGY &KIND O BASIS_SET TZVP-MOLOPT-GTH-q6 POTENTIAL GTH-PBE-q6 &END KIND &KIND Ti BASIS_SET DZVP-MOLOPT-SR-GTH-q12 POTENTIAL GTH-PBE-q12 &END KIND &END SUBSYS STRESS_TENSOR ANALYTICAL &END FORCE_EVAL &MOTION &CELL_OPT TYPE GEO_OPT OPTIMIZER CG MAX_ITER 1000 KEEP_ANGLES T &CG &LINE_SEARCH TYPE 2PNT &END LINE_SEARCH &END CG &END CELL_OPT &GEO_OPT TYPE minimization OPTIMIZER BFGS MAX_ITER 1000 &END GEO_OPT &PRINT &TRAJECTORY &EACH CELL_OPT 1 &END EACH &END TRAJECTORY &STRESS &END STRESS &END PRINT &END MOTION the starting geometry was taken from litterature Ti 0.000000000 0.000000000 0.000000000 Ti 1.888000000 1.888000000 4.743000000 Ti 0.000000000 1.888000000 2.372000000 Ti 1.888000000 0.000000000 7.114000000 O 0.000000000 0.000000000 1.973000000 O 1.888000000 1.888000000 6.716000000 O 0.000000000 1.888000000 <a href="tel:4.345000000" value="+14345000000">4.345000000</a> O 1.888000000 0.000000000 <a href="tel:9.088000000" value="+19088000000">9.088000000</a> O 1.888000000 0.000000000 5.141000000 O 0.000000000 1.888000000 0.398000000 O 1.888000000 1.888000000 2.770000000 O 0.000000000 0.000000000 7.513000000 Ti 3.776000000 0.000000000 0.000000000 Ti 5.664000000 1.888000000 4.743000000 Ti 3.776000000 1.888000000 2.372000000 Ti 5.664000000 0.000000000 7.114000000 O 3.776000000 0.000000000 1.973000000 O 5.664000000 1.888000000 6.716000000 O 3.776000000 1.888000000 <a href="tel:4.345000000" value="+14345000000">4.345000000</a> O 5.664000000 0.000000000 <a href="tel:9.088000000" value="+19088000000">9.088000000</a> O 5.664000000 0.000000000 5.141000000 O 3.776000000 1.888000000 0.398000000 O 5.664000000 1.888000000 2.770000000 O 3.776000000 0.000000000 7.513000000 Ti 0.000000000 3.776000000 0.000000000 Ti 1.888000000 5.664000000 4.743000000 Ti 0.000000000 5.664000000 2.372000000 Ti 1.888000000 3.776000000 7.114000000 O 0.000000000 3.776000000 1.973000000 O 1.888000000 5.664000000 6.716000000 O 0.000000000 5.664000000 4.345000000 O 1.888000000 3.776000000 9.088000000 O 1.888000000 3.776000000 5.141000000 O 0.000000000 5.664000000 0.398000000 O 1.888000000 5.664000000 2.770000000 O 0.000000000 3.776000000 7.513000000 Ti 3.776000000 3.776000000 0.000000000 Ti 5.664000000 5.664000000 4.743000000 Ti 3.776000000 5.664000000 2.372000000 Ti 5.664000000 3.776000000 7.114000000 O 3.776000000 3.776000000 1.973000000 O 5.664000000 5.664000000 6.716000000 O 3.776000000 5.664000000 4.345000000 O 5.664000000 3.776000000 9.088000000 O 5.664000000 3.776000000 5.141000000 O 3.776000000 5.664000000 0.398000000 O 5.664000000 5.664000000 2.770000000 O 3.776000000 3.776000000 7.513000000 Ti 0.000000000 0.000000000 9.486000000 Ti 1.888000000 1.888000000 14.229000000 Ti 0.000000000 1.888000000 11.858000000 Ti 1.888000000 0.000000000 16.601000000 O 0.000000000 0.000000000 11.459000000 O 1.888000000 1.888000000 16.202000000 O 0.000000000 1.888000000 13.831000000 O 1.888000000 0.000000000 18.574000000 O 1.888000000 0.000000000 14.627000000 O 0.000000000 1.888000000 9.884000000 O 1.888000000 1.888000000 12.256000000 O 0.000000000 0.000000000 16.999000000 Ti 3.776000000 0.000000000 9.486000000 Ti 5.664000000 1.888000000 14.229000000 Ti 3.776000000 1.888000000 11.858000000 Ti 5.664000000 0.000000000 16.601000000 O 3.776000000 0.000000000 11.459000000 O 5.664000000 1.888000000 16.202000000 O 3.776000000 1.888000000 13.831000000 O 5.664000000 0.000000000 18.574000000 O 5.664000000 0.000000000 14.627000000 O 3.776000000 1.888000000 9.884000000 O 5.664000000 1.888000000 12.256000000 O 3.776000000 0.000000000 16.999000000 Ti 0.000000000 3.776000000 9.486000000 Ti 1.888000000 5.664000000 14.229000000 Ti 0.000000000 5.664000000 11.858000000 Ti 1.888000000 3.776000000 16.601000000 O 0.000000000 3.776000000 11.459000000 O 1.888000000 5.664000000 16.202000000 O 0.000000000 5.664000000 13.831000000 O 1.888000000 3.776000000 18.574000000 O 1.888000000 3.776000000 14.627000000 O 0.000000000 5.664000000 9.884000000 O 1.888000000 5.664000000 12.256000000 O 0.000000000 3.776000000 16.999000000 Ti 3.776000000 3.776000000 9.486000000 Ti 5.664000000 5.664000000 14.229000000 Ti 3.776000000 5.664000000 11.858000000 Ti 5.664000000 3.776000000 16.601000000 O 3.776000000 3.776000000 11.459000000 O 5.664000000 5.664000000 16.202000000 O 3.776000000 5.664000000 13.831000000 O 5.664000000 3.776000000 18.574000000 O 5.664000000 3.776000000 14.627000000 O 3.776000000 5.664000000 9.884000000 O 5.664000000 5.664000000 12.256000000 O 3.776000000 3.776000000 16.999000000 thanks in advace Alessandro -- You received this message because you are subscribed to the Google Groups "cp2k" group. To post to this group, send email to <a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a>. To unsubscribe from this group, send email to <a href="mailto:cp2k%2Bun...@googlegroups.com">cp2k+uns...@googlegroups.com</a>. For more options, visit this group at <a href="http://groups.google.com/group/cp2k?hl=en" target="_blank">http://groups.google.com/group/cp2k?hl=en</a>. </blockquote></div>