<div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div>Dear all,<br><br>I use the cp2k (5.1) to optimize a cell of TiO2. Below is the main input,<br>&GLOBAL<br>  RUN_TYPE  CELL_OPT<br>&END GLOBAL<br>&MOTION<br>  &CELL_OPT<br>    OPTIMIZER  BFGS<br>   &END CELL_OPT<br>&END MOTION<br>  &FORCE_EVAL<br>  METHOD  QS<br>  STRESS_TENSOR  ANALYTICAL<br>  &DFT<br>          BASIS_SET_FILE_NAME ${DATAPATH}/BASIS_MOLOPT<br>          POTENTIAL_FILE_NAME ${DATAPATH}/GTH_POTENTIALS<br>          &SCF<br>                   &OT  T<br>                 ..<br>                  &END OT<br>          &END SCF<br>          &QS<br>                  METHOD  GPW<br>          &END QS<br>          &MGRID<br>                  CUTOFF   400<br>          &END MGRID<br>          &XC<br>                  &XC_FUNCTIONAL  NO_SHORTCUT<br>                          &PBE  T<br>                          &END PBE<br>                  &END XC_FUNCTIONAL<br>                   &vdW_POTENTIAL<br>                    DISPERSION_FUNCTIONAL PAIR_POTENTIAL<br>                           &PAIR_POTENTIAL<br>                           TYPE DFTD3<br>                               CALCULATE_C9_TERM .TRUE.<br>                                 REFERENCE_C9_TERM .TRUE.<br>                                 LONG_RANGE_CORRECTION .TRUE.<br>                                  PARAMETER_FILE_NAME ${DATAPATH}/dftd3.dat<br>                                  VERBOSE_OUTPUT .FALSE.<br>                                  REFERENCE_FUNCTIONAL PBE<br>                                  R_CUTOFF [angstrom] 9.0<br>                                  EPS_CN 1.0E-6<br>                          &END PAIR_POTENTIAL<br>                               &END vdW_POTENTIAL<br>      &END XC<br>     &END DFT<br>  &SUBSYS<br>          &CELL<br>                  ABC 4.59400 4.59400 2.95900<br>                  ALPHA_BETA_GAMMA 90.0 90.0 90.0<br>                  PERIODIC  XYZ<br>                  SYMMETRY TETRAGONAL<br>                  MULTIPLE_UNIT_CELL  3 3 4<br>          &END CELL<br>          &COORD<br>                  Ti     0.0000    0.0000    0.0000<br>                  Ti     2.2970    2.2970    1.4795<br>                  O      1.4003    1.4003    0.0000<br>                  O      3.1937    3.1937    0.0000<br>                  O      0.8967    3.6973    1.4795<br>                  O      3.6973    0.8967    1.4795<br>          &END COORD<br>          &KIND Ti<br>                  BASIS_SET DZVP-MOLOPT-SR-GTH<br>                  POTENTIAL GTH-PBE-q12<br>          &END KIND<br>          &KIND O<br>                  BASIS_SET TZVP-MOLOPT-GTH<br>                  POTENTIAL GTH-PBE-q6<br>          &END KIND<br>          &TOPOLOGY<br>                  MULTIPLE_UNIT_CELL  3 3 4<br>          &END TOPOLOGY<br>  &END SUBSYS<br>&END FORCE_EVAL<br><br>It is convergent after 9 step. The energy changes as below in these steps:<br>  -6514.202116775491959<br>  -6514.107348731997263<br>  -6514.100302314682267<br>  -6514.121769318782754<br>  -6514.123121857887782<br>  -6514.122521243046322<br>  -6514.121260371050994<br>  -6514.120835064291896<br>  -6514.120835064288258<br>It is clear that the first step has the lowest energy. When I change the vDW correction to below:<br> &vdW_POTENTIAL<br>    DISPERSION_FUNCTIONAL NON_LOCAL<br>    &NON_LOCAL<br>      TYPE DRSLL<br>      VERBOSE_OUTPUT<br>      KERNEL_FILE_NAME /lustre/home/jiajf/software/cp2k30/cp2k/cp2k/data/vdW_kernel_table.dat<br>      CUTOFF  80<br>    &END NON_LOCAL<br> &END vdW_POTENTIAL<br>The energy changes as below,<br>  -6501.667309011268117<br>  -6501.552098176282016<br>  -6501.683944202200109<br>  -6501.684511798672247<br>  -6501.691681789144241<br>  -6501.691989256092711<br>  -6501.692075269643283<br>  -6501.692160170975512<br>  -6501.692235978556710<br>  -6501.692261498596054<br>  -6501.692262177740304<br>  -6501.692262178249621<br><br>So, I think that there is a bug for CELL_OPT with DFT-D3 correction.<br><br>Jianfeng Jia<br><br><br><br></div></div><br><br><span title="neteasefooter"><p> </p></span>