<div>Dear CP2K users,<br></div><div>I am trying to perform the protonation and deprotonation of liquid formic acid  with the CP2K metadynamics method.</div><div>I have used the formic acid oxygen coordination numbers as the collective variables. The chosen collective coordinates</div>


<div>are the coordination numbers of the carboxyl oxygen atoms (two oxygen atom) to all other hydroxyl hydrogern [only the O-H hydrogen].</div><div>Using these generalized coordinates, it should be, the nutral formic acid coordination number Co-h ~ 1, The protonated </div>


<div>formic acid coordination number Co-h~2 and deprotonated (formate ion) formic acid coodination number Co-h~0. </div><div>But the coordination number are found different from its ideal value (less than 1). For the nutral formic acid  Co-h ~ 0.5,</div>

<div>protonated formic acid coordination number Co-h~0.9 and deprotonated (formate ion) formic acid coodination number Co-h~.1 <br></div><div>I have used R0=1.6 angstrom in the coordination function. How can I solve this problem?</div>

<div><br></div><div>This is  my input file. <br>&GLOBAL<br>  PRINT_LEVEL                      LOW<br>  PROJECT                          FOH<br>  PROGRAM                          CP2K<br>  RUN_TYPE                         MD<br>

  WALLTIME                         43000<br>&END GLOBAL<br>    <br>&MOTION<br>  &MD<br>    ENSEMBLE                       NVT<br>    STEPS                          8000<br>    TIMESTEP                       0.5<br>

    TEMPERATURE                    300.0<br>    &THERMOSTAT<br>      TYPE                         NOSE<br>      REGION                       MOLECULE<br>      &NOSE<br>        LENGTH                     3<br>        YOSHIDA                    3<br>

        TIMECON                    100<br>        MTS                        2<br>      &END NOSE<br>    &END THERMOSTAT<br>    &PRINT<br>      &ENERGY<br>        &EACH<br>          MD                       1<br>

        &END EACH                  <br>        FILENAME                   =FOH.ene<br>      &END ENERGY<br>    &END PRINT<br>  &END MD<br># DO METADYNAMICS EVERY 20 STEPS (10 fs) with 1.0 kcal/mol HEIGHT<br>

  &FREE_ENERGY<br>    METHOD                         METADYN<br>    &METADYN<br>      DO_HILLS<br>      NT_HILLS                     20<br>      WW                           0.0016<br>      &METAVAR<br>        COLVAR                     1<br>

        SCALE                      0.05<br>      &END METAVAR<br>      &PRINT<br>        &COLVAR<br>          FILENAME                 =colvar<br>          &EACH<br>            MD                     20<br>

          &END EACH<br>        &END COLVAR<br>        &HILLS<br>          FILENAME                 =hills<br>          &EACH<br>            MD                     20<br>          &END EACH<br>        &END HILLS<br>

      &END PRINT<br>    &END METADYN<br>  &END FREE_ENERGY<br>  &PRINT<br>    &TRAJECTORY                    SILENT<br>      &EACH       <br>        MD                         10<br>      &END EACH<br>

      FILENAME                     =FOH.dcd<br>      FORMAT                       DCD<br>    &END TRAJECTORY<br>    &VELOCITIES                    OFF<br>      &EACH       <br>        MD                         10<br>

      &END EACH<br>      FILENAME                     =FOH.vel<br>    &END VELOCITIES<br>    &FORCES                        OFF<br>      &EACH       <br>        MD                         10<br>      &END EACH<br>

      FILENAME                     =FOH.for<br>    &END FORCES<br>    &RESTART_HISTORY               OFF<br>    &END RESTART_HISTORY<br>    &RESTART                       SILENT<br>      &EACH        <br>

        MD                         10<br>      &END EACH<br>      FILENAME                     =FOH.restart<br>    &END RESTART<br>  &END PRINT<br>&END MOTION<br> <br>&FORCE_EVAL<br>  METHOD                           QUICKSTEP<br>

  &DFT<br>    BASIS_SET_FILE_NAME            ./BASIS_SET<br>    POTENTIAL_FILE_NAME            ./POTENTIAL<br>    CHARGE                         0<br>    &SCF<br>      MAX_SCF                      40<br>      EPS_SCF                      1.0E-6<br>

      SCF_GUESS                    RESTART<br>      &OUTER_SCF<br>        EPS_SCF                    1.0E-6<br>        MAX_SCF                    10<br>      &END OUTER_SCF<br>      &OT<br>        PRECONDITIONER             FULL_ALL<br>

        MINIMIZER                  DIIS<br>        N_DIIS                     7<br>      &END OT<br>      &PRINT<br>        &RESTART<br>          &EACH <br>            MD                     10<br>          &END EACH<br>

          FILENAME                 =RESTART<br>        &END RESTART<br>        &RESTART_HISTORY           OFF<br>        &END RESTART_HISTORY<br>      &END PRINT<br>    &END SCF<br>    &QS<br>      EPS_DEFAULT                  1.0E-12<br>

      EXTRAPOLATION                ASPC<br>      EXTRAPOLATION_ORDER          3<br>    &END QS<br><br>    &MGRID<br>      CUTOFF                       280<br>      COMMENSURATE<br>    &END MGRID<br>    &POISSON<br>

#      POISSON_SOLVER               MT<br>      POISSON_SOLVER               PERIODIC<br>      PERIODIC                     XYZ<br>    &END POISSON<br>    &XC<br>      &XC_GRID<br>        XC_SMOOTH_RHO              NN10<br>

        XC_DERIV                   SPLINE2_SMOOTH<br>      &END XC_GRID<br>      &XC_FUNCTIONAL               BLYP<br>      &END XC_FUNCTIONAL<br>    &END XC<br>  &END DFT<br>  &SUBSYS<br>    &CELL<br>

      ABC                          12.60 12.60 12.60<br>      PERIODIC                     XYZ<br>    &END CELL<br>    &COORD<br> O         6.459781        8.056508        6.296098<br> C         7.163456        7.125041        6.732669<br>

 H         8.182514        7.323334        7.066482<br> O         6.770119        5.821413        6.822736<br> H         5.718549        5.683926        6.697456<br> O         6.909952        2.509184        6.347867<br>
 C         7.896109        2.851522        5.707026<br>
 H         8.661729        2.175128        5.302803<br> O         8.236772        4.119331        5.434266<br> H         7.643341        4.773784        5.856131<br> O         4.124040        4.748510        6.367797<br>
 C         3.826171        4.079831        7.413561<br>
 H         2.911557        4.162765        8.057558<br> O         4.702719        3.252897        7.940200<br> H         5.495648        3.098516        7.276470<br> O         7.083500        0.801447       10.623640<br>
 C         7.196982        1.634820        9.706008<br>
 H         7.778468        1.371844        8.765636<br> O         6.640886        2.809737        9.611978<br> H         6.021287        2.908125       10.412297<br> O         8.489833        2.288351        2.455063<br>
 C         7.679999        1.503715        1.953385<br>
 H         8.004016        0.575160        1.499982<br> O         6.331616        1.743520        1.861442<br> H         6.295148        2.780825        2.098260<br> O         5.664177       -0.290593        5.373825<br>
 C         5.056596        0.661018        4.942813<br>
 H         5.121344        1.018664        3.844198<br> O         4.048135        1.244555        5.708744<br> H         3.943226        0.801882        6.633520<br> O         7.351965        7.140197        3.238899<br>
 C         7.307747        7.292219        1.957629<br>
 H         6.386861        6.950826        1.436370<br> O         8.327481        7.875422        1.353614<br> H         9.120440        7.978032        2.056322<br> O         6.106112        4.268650        2.299097<br>
 C         5.799206        4.316004        3.548140<br>
 H         5.556844        3.381579        4.156157<br> O         5.770873        5.431324        4.260241<br> H         6.278060        6.218091        3.789728<br> O         3.084212        1.479342        1.755576<br>
 C         3.258946        0.396132        1.125847<br>
 H         2.508868       -0.427617        0.964556<br> O         4.406919        0.180757        0.419176<br> H         5.169578        0.758113        0.719269<br> O         1.030561        0.825643       10.008227<br>
 C         1.783958        1.802656       10.248734<br>
 H         1.407950        2.761985       10.678268<br> O         3.112659        1.847893       10.048674<br> H         3.554449        1.216543        9.380070<br> O         1.253780        8.870214        6.225453<br>
 C         2.257224        9.397345        6.729775<br>
 H         2.508456        9.461020        7.787119<br> O         3.297263        9.862703        6.012998<br> H         3.096095        9.917562        5.000798<br> O        10.369401        8.316547        2.866836<br>
 C        10.256690        8.249763        4.106692<br>
 H        11.083242        8.538807        4.860478<br> O         9.137828        7.985956        4.735631<br> H         8.392881        7.628317        4.134091<br> O         3.664910        8.385721        9.219956<br>
 C         3.550214        7.189969        8.825279<br>
 H         2.623363        6.887540        8.267633<br> O         4.336981        6.125011        9.051637<br> H         5.276801        6.492500        9.468660<br> O         8.113374       10.054495        3.054541<br>
 C         8.286448       10.528097        4.157214<br>
 H         7.710155       10.320824        5.027996<br> O         9.242023       11.434313        4.468067<br> H         9.756812       11.726453        3.660706<br> O         5.005743        3.012838       -0.012323<br>
 C         4.081765        3.819001       -0.253009<br>
 H         4.127414        4.654782       -0.914101<br> O         2.967043        3.883029        0.461207<br> H         3.039859        3.176162        1.154938<br> O        10.165725        1.229098        7.008693<br>
 C        11.367460        1.165506        6.562970<br>
 H        11.958104        1.960840        6.127166<br> O        12.027848       -0.013202        6.390440<br> H        11.371208       -0.740315        6.692291<br> O        -0.577225        2.282373        0.646075<br>
 C        -1.509503        2.225770       -0.132934<br>
 H        -2.561031        2.545444        0.052443<br> O        -1.456205        1.662727       -1.378040<br> H        -0.442135        1.330523       -1.489236<br> O        10.555040       10.968234        0.593169<br>
 C         9.888683       10.093122        0.035767<br>
 H         9.998981        9.004327        0.174939<br> O         8.964099       10.379899       -0.924083<br> H         8.565263       11.297233       -0.849804<br> O         3.094378        3.894949        3.453685<br>
 C         2.021610        3.445151        3.836126<br>
 H         1.122624        3.749433        3.311372<br> O         1.893391        2.434526        4.709074<br> H         2.763960        1.996969        4.955929<br> O        12.020802        6.427450        8.220920<br>
 C        11.180152        7.342253        7.997811<br>
 H        11.525702        8.056501        7.226946<br>O         9.987535        7.436066        8.557799</div><div>H         9.950028        6.658945        9.303061<br> O         9.629528        5.870730       10.381703<br>

 C         8.465271        5.367125       10.270255<br> H         7.920763        5.583338        9.386205<br> O         7.791088        4.762825       11.277155<br> H         8.324699        4.746763       12.211556<br>
 O         4.045846        7.058285        0.448421<br>
 C         3.246323        6.761549        1.412440<br> H         3.356992        5.865156        2.077310<br> O         2.183205        7.514649        1.741086<br> H         1.976016        8.233811        1.062838<br>
 O        -0.451564       12.476867        3.249723<br>
 C         0.566046       11.747444        3.399303<br> H         1.397718       11.965692        4.095191<br> O         0.695218       10.573921        2.704840<br> H        -0.053107       10.576586        2.007093<br>
 O         9.430169        5.225144        1.778048<br>
 C        10.237226        5.055058        2.698643<br> H        10.612823        5.903150        3.198559<br> O        10.855284        3.912604        2.999382<br> H        10.529005        3.202497        2.361735<br>
 O         0.846705        3.461511        8.238902<br>
 C        -0.265138        3.819748        7.859488<br> H        -1.132885        3.533797        8.471083<br> O        -0.557023        4.409714        6.672273<br> H         0.226207        4.844563        6.169906<br>
 O         6.434192        7.355910        9.595535<br>
 C         6.480993        8.513487       10.088883<br> H         7.201953        9.328683        9.902081<br> O         5.629369        8.917621       11.020820<br> H         4.860280        8.266977       11.197220<br>
 O        10.320602       -1.683661        7.327907<br>
 C         9.149270       -1.608931        7.760573<br> H         8.590673       -2.490773        8.186227<br> O         8.443110       -0.475193        7.935741<br> H         9.168722        0.226790        7.666053<br>
 O         3.835103       10.431785        3.477700<br>
 C         4.705925        9.685083        2.972356<br> H         5.352604       10.006369        2.152012<br> O         5.046082        8.433438        3.400453<br> H         4.462333        8.127420        4.144083<br>
 O         2.098257        9.312925       -0.191389<br>
 C         1.380951        9.650267       -1.202713<br> H         1.663358       10.483579       -1.757955<br> O         0.226948        9.120008       -1.541336<br> H         0.138752        8.172229       -1.133408<br>
 O         4.106698       11.990078        8.211988<br>
 C         4.870600       11.082915        8.660361<br> H         4.793638       10.787877        9.754473<br> O         5.595374       10.290161        7.911755<br> H         5.358137       10.538576        6.923987<br>
 O         0.882067        5.860265        4.738442<br>
 C         1.727164        6.738016        4.539868<br> H         1.438878        7.659225        4.038307<br> O         3.044999        6.761288        4.882832<br> H         3.349001        5.950273        5.432134<br>
 O         0.102684        7.049788       11.618558<br>
 C         0.730715        5.954988       11.473636<br> H         0.699110        5.214057       12.217627<br> O         1.387672        5.606141       10.400733<br> H         1.013165        5.950356        9.473770<br>
    &END COORD<br>
    &COLVAR<br>       &COORDINATION<br>          ATOMS_FROM 1 4<br>          ATOMS_TO 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85<br>  ATOMS_TO 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160<br>          R_0 [angstrom]  1.6<br>

          NN  6<br>          ND  18<br>       &END COORDINATION<br>    &END COLVAR<br>    &KIND                          H<br>      BASIS_SET                    DZVP-GTH-BLYP<br>      POTENTIAL                    GTH-BLYP-q1<br>

    &END KIND<br>    &KIND                          C<br>      BASIS_SET                    DZVP-GTH-BLYP<br>      POTENTIAL                    GTH-BLYP-q4<br>    &END KIND<br>    &KIND                          O<br>

      BASIS_SET                    DZVP-GTH-BLYP<br>      POTENTIAL                    GTH-BLYP-q6<br>    &END KIND<br>    &PRINT<br>      &MOLECULES<br>      &END MOLECULES<br>    &END PRINT<br>  &END SUBSYS<br>

&END FORCE_EVAL<br><br></div><div>This is my HILLS file</div><div>        10.0      0.54429      0.05000      0.00160<br>        20.0      0.52151      0.05000      0.00160<br>        30.0      0.50277      0.05000      0.00160<br>

        40.0      0.49177      0.05000      0.00160<br>        50.0      0.48283      0.05000      0.00160<br>        60.0      0.48205      0.05000      0.00160<br>        70.0      0.48504      0.05000      0.00160<br>
        80.0      0.48519      0.05000      0.00160<br>
        90.0      0.48598      0.05000      0.00160<br>       100.0      0.48460      0.05000      0.00160<br>       110.0      0.47717      0.05000      0.00160<br>       120.0      0.46886      0.05000      0.00160<br>
       130.0      0.46423      0.05000      0.00160<br>
       140.0      0.47542      0.05000      0.00160<br>       150.0      0.48298      0.05000      0.00160<br>       160.0      0.47676      0.05000      0.00160<br>       170.0      0.45979      0.05000      0.00160<br>
       180.0      0.48752      0.05000      0.00160<br>
       190.0      0.46446      0.05000      0.00160<br>       200.0      0.49344      0.05000      0.00160<br>       210.0      0.57036      0.05000      0.00160<br>       220.0      0.64062      0.05000      0.00160<br>
       230.0      0.76264      0.05000      0.00160<br>
       240.0      0.84557      0.05000      0.00160<br>       250.0      0.66548      0.05000      0.00160<br>       260.0      0.67990      0.05000      0.00160<br>       270.0      0.63364      0.05000      0.00160<br>
       280.0      0.59721      0.05000      0.00160<br>
       290.0      0.55210      0.05000      0.00160<br>       300.0      0.57908      0.05000      0.00160<br>       310.0      0.70571      0.05000      0.00160<br>       320.0      0.84142      0.05000      0.00160<br>
       330.0      0.78512      0.05000      0.00160<br>
       340.0      0.68261      0.05000      0.00160<br>       350.0      0.64575      0.05000      0.00160<br>       360.0      0.61974      0.05000      0.00160<br>       370.0      0.59782      0.05000      0.00160<br>
       380.0      0.63271      0.05000      0.00160<br>
       390.0      0.69847      0.05000      0.00160<br>-------------------------------------------<br></div><div>-------------------------------------------</div><div>Thanks</div><div>Sonali</div><div><br></div>