<div dir="ltr">I am attempting to run a geometry optimization on MgSi2O3 using a Buckingham potential. I attempted to include a three-body interaction among the Si-O, but it does not appear to have any effect at all on the outcome. I've attempted to adjust the force constant, but no difference in final result. Am I missing the meaning of this section?<div> </div><div>Furthermore, I would like to (for testing purposes) eliminate the Mg-Si electrostatic interaction, but am unsure how to do this. Is there a way to exclude this interaction?</div><div> </div><div>Thanks.</div><div> </div><div>-Christopher Mauney</div><div> </div><div>input file:</div><div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex;"> &GLOBAL BLACS_GRID SQUARE BLACS_REPEATABLE F PREFERRED_DIAG_LIBRARY SL PREFERRED_FFT_LIBRARY FFTW3 FFTW_WISDOM_FILE_NAME /etc/fftw/wisdom FFTW_PLAN_TYPE ESTIMATE EXTENDED_FFT_LENGTHS F FFT_POOL_SCRATCH_LIMIT 15 ALLTOALL_SGL F PRINT_LEVEL LOW PROGRAM_NAME CP2K PROJECT_NAME sigen-test OUTPUT_FILE_NAME RUN_TYPE GEO_OPT WALLTIME ECHO_INPUT F ECHO_ALL_HOSTS F TRACE F TRACE_MASTER T TRACE_MAX 2147483647 FLUSH_SHOULD_FLUSH T CALLGRAPH NONE CALLGRAPH_FILE_NAME SEED 2000 SAVE_MEM F ENABLE_UNSUPPORTED_FEATURES F &END GLOBAL &MOTION &GEO_OPT TYPE MINIMIZATION OPTIMIZER BFGS MAX_ITER 100 MAX_DR 1.0000000000000000E-04 MAX_FORCE 1.0000000000000001E-05 RMS_DR 1.5000000000000000E-03 RMS_FORCE 2.9999999999999997E-04 STEP_START_VAL 0 &BFGS TRUST_RADIUS 2.5000000000000000E-01 USE_MODEL_HESSIAN T USE_RAT_FUN_OPT F RESTART_HESSIAN F RESTART_FILE_NAME &RESTART OFF ADD_LAST NUMERIC COMMON_ITERATION_LEVELS 2 FILENAME BFGS LOG_PRINT_KEY F &END RESTART &END BFGS &END GEO_OPT &PRINT &TRAJECTORY SILENT ADD_LAST NUMERIC COMMON_ITERATION_LEVELS 1 FILENAME LOG_PRINT_KEY F UNIT angstrom FORMAT XMOL CHARGE_OCCUP F CHARGE_BETA F CHARGE_EXTENDED F &EACH JUST_ENERGY 1 POWELL_OPT 1 QS_SCF 1 XAS_SCF 1 MD 1 METADYNAMICS 1 GEO_OPT 1 ROT_OPT 1 CELL_OPT 1 BAND 1 EP_LIN_SOLVER 1 SPLINE_FIND_COEFFS 1 REPLICA_EVAL 1 BSSE 1 SHELL_OPT 1 &END EACH &END TRAJECTORY &RESTART OFF ADD_LAST NUMERIC COMMON_ITERATION_LEVELS 1 FILENAME LOG_PRINT_KEY F BACKUP_COPIES 3 SPLIT_RESTART_FILE F &END RESTART &RESTART_HISTORY OFF ADD_LAST NO COMMON_ITERATION_LEVELS 0 FILENAME LOG_PRINT_KEY F &END RESTART_HISTORY &END PRINT &END MOTION &FORCE_EVAL METHOD FIST STRESS_TENSOR NONE &MM &FORCEFIELD PARMTYPE OFF VDW_SCALE14 1.0000000000000000E+00 EI_SCALE14 0.0000000000000000E+00 SHIFT_CUTOFF T DO_NONBONDED T IGNORE_MISSING_CRITICAL_PARAMS F MULTIPLE_POTENTIAL F ZBL_SCATTERING F &SPLINE R0_NB 1.0000000000000001E-01 RCUT_NB -1.0000000000000000E+00 EMAX_SPLINE 1.0000000000000000E+02 EMAX_ACCURACY 2.0000000000000000E-02 EPS_SPLINE 9.9999999999999995E-08 NPOINTS -1 UNIQUE_SPLINE F &END SPLINE &NONBONDED &WILLIAMS ATOMS O O A 2.6416495841429514E+08 B 6.7114093959731544E+00 C 3.2353360747630242E+05 RCUT 1.0000000000000002E+01 &END WILLIAMS &WILLIAMS ATOMS Si O A 1.4899105572958285E+07 B 3.1199301135654558E+00 C 1.2372236150635568E+05 RCUT 1.0000000000000002E+01 &END WILLIAMS &WILLIAMS ATOMS Si Si A 9.2258269084930563E+08 B 4.9751243781094523E+00 C 5.1846608733236147E+06 RCUT 1.0000000000000002E+01 &END WILLIAMS &WILLIAMS ATOMS Mg O A 9.5342615460017957E+06 B 3.0845157310302285E+00 C 0.0000000000000000E+00 RCUT 1.0000000000000002E+01 &END WILLIAMS &WILLIAMS ATOMS Mg Si A 0.0000000000000000E+00 B 0.0000000000000000E+00 C 0.0000000000000000E+00 RCUT 1.0000000000000002E+01 &END WILLIAMS &WILLIAMS ATOMS Mg Mg A 0.0000000000000000E+00 B 0.0000000000000000E+00 C 0.0000000000000000E+00 RCUT 1.0000000000000002E+01 &END WILLIAMS &END NONBONDED &CHARGE ATOM O CHARGE -2.0000000000000000E+00 &END CHARGE &CHARGE ATOM SI CHARGE 4.0000000000000000E+00 &END CHARGE &CHARGE ATOM MG CHARGE 2.0000000000000000E+00 &END CHARGE &BEND ATOMS O SI O KIND HARMONIC K 2.0972000000000000E+00 CB 0.0000000000000000E+00 R012 0.0000000000000000E+00 R032 0.0000000000000000E+00 KBS12 0.0000000000000000E+00 KBS32 0.0000000000000000E+00 KSS 0.0000000000000000E+00 THETA0 1.9106119321581925E+00 &END BEND &BEND ATOMS O MG O KIND HARMONIC K 2.0972000000000000E+00 CB 0.0000000000000000E+00 R012 0.0000000000000000E+00 R032 0.0000000000000000E+00 KBS12 0.0000000000000000E+00 KBS32 0.0000000000000000E+00 KSS 0.0000000000000000E+00 THETA0 1.5707963267948966E+00 &END BEND &END FORCEFIELD &POISSON POISSON_SOLVER ANALYTIC PERIODIC NONE &EWALD EWALD_TYPE NONE EWALD_ACCURACY 9.9999999999999995E-07 ALPHA 3.4999999999999998E-01 NS_MAX 11 O_SPLINE 6 EPSILON 9.9999999999999995E-07 &END EWALD &END POISSON &END MM &SUBSYS &CELL ABC 2.0000000000000004E+01 2.0000000000000004E+01 2.0000000000000004E+01 ALPHA_BETA_GAMMA 9.0000000000000000E+01 9.0000000000000000E+01 9.0000000000000000E+01 CELL_FILE_FORMAT CP2K PERIODIC NONE MULTIPLE_UNIT_CELL 1 1 1 SYMMETRY NONE &END CELL &TOPOLOGY CHARGE_OCCUP F CHARGE_BETA F CHARGE_EXTENDED F PARA_RES T MOL_CHECK T USE_G96_VELOCITY F COORD_FILE_NAME mgsi-test.xyz COORD_FILE_FORMAT XYZ NUMBER_OF_ATOMS -1 CONN_FILE_FORMAT GENERATE DISABLE_EXCLUSION_LISTS F EXCLUDE_VDW 1-3 EXCLUDE_EI 1-3 AUTOGEN_EXCLUDE_LISTS F MULTIPLE_UNIT_CELL 1 1 1 MEMORY_PROGRESSION_FACTOR 1.2000000000000000E+00 &END TOPOLOGY &END SUBSYS &END FORCE_EVAL</blockquote></div><div> </div><div>mgsi-test.xyz:</div><div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex;">6</blockquote><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex;"> </blockquote><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex;">Si 5.100733801 7.021427036 5.000000000 Si 8.599266199 7.021427036 5.000000000 O 6.850000000 7.149878576 5.000000000 O 5.000213137 5.388401447 5.000000000 O 8.699786863 5.388401447 5.000000000 Mg 6.850000000 5.000464458 5.000000000</blockquote></div><div> </div></div>