<div dir="ltr">Hi everyone, I am trying to do DFTB calculations with CP2K 5.1 and encountered a Problem with geometry optimizations. They give unreasonable results when compared to e.g. the DFTB implementation from SCM using the same parameter files. My input looks like this: &GLOBAL PROJECT foo RUN_TYPE GEO_OPT PRINT_LEVEL LOW &END GLOBAL &FORCE_EVAL METHOD QS &DFT &MGRID CUTOFF 500 &END MGRID &QS METHOD DFTB &DFTB SELF_CONSISTENT T ! DO_EWALD T ! DISPERSION T &PARAMETER SK_FILE H H H-H.skf SK_FILE H C H-C.skf SK_FILE H N H-N.skf SK_FILE C H C-H.skf SK_FILE C C C-C.skf SK_FILE C N C-N.skf SK_FILE N H N-H.skf SK_FILE N C N-C.skf SK_FILE N N N-N.skf PARAM_FILE_PATH /home/Luyj/test/cp2k510/data/DFTB/pbc-0-3/ #PARAM_FILE_NAME pbc-0-3_parameter #UFF_FORCE_FIELD uff_table &END PARAMETER &END DFTB &END QS &POISSON ! Non periodic calculation needs Poisson solver PERIODIC NONE PSOLVER WAVELET &END POISSON &SCF MAX_SCF 30 EPS_SCF 1.0E-6 SCF_GUESS ATOMIC &OT MINIMIZER DIIS PRECONDITIONER FULL_SINGLE_INVERSE &END &END SCF &END DFT &SUBSYS &CELL ABC 15.3244190216000007 15.3244190216000007 21.6720008849999992 &END CELL &COORD C 0.08264 1.07231 2.21147 C 0.68453 1.52676 4.69495 C 2.18931 1.96511 6.69587 C 0.98053 1.35688 3.35205 N 1.88574 1.77281 5.28497 N 2.88240 1.74848 4.37073 N 2.33681 1.50117 3.20562 H -0.23852 1.48611 5.25945 H 3.23838 2.13910 6.81449 H 1.90876 1.08978 7.24358 H 1.64387 2.80778 7.06643 H 0.65868 1.00469 1.31231 H -0.63478 1.86052 2.11702 H -0.42548 0.14586 2.38006 &END COORD &END SUBSYS &END FORCE_EVAL &MOTION &GEO_OPT TYPE MINIMIZATION MAX_DR 1.0E-03 MAX_FORCE 1.0E-03 RMS_DR 1.0E-03 RMS_FORCE 1.0E-03 MAX_ITER 50 OPTIMIZER CG &CG MAX_STEEP_STEPS 0 RESTART_LIMIT 9.0E-01 &END CG &END GEO_OPT &END MOTION The parameters are taken unmodified as supplied from DFTB.org. I attach the results of the optimization as a movie. I hope someone with experience with the code can help me find the error. Best regards, Jan-Niclas Luy </div>