<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>