Bend potential having no effect & excluding specific electrostatic interactions

Christopher Mauney christop... at gmail.com
Mon Feb 16 22:14:03 UTC 2015


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?

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?

Thanks.

-Christopher Mauney

input file:

>  &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


mgsi-test.xyz:

> 6

 

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


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