Modeling the Montmorillonite

Hello

I would like to ask a few questions about modelling the Montmorillonite.

I built a model of Na+MMT using those two papers

S. I. Tsipursky, V. A. Drits, Clay Minerals 19 (1984) 177-193.

R. Toth, A. Coslanich, M. Ferrone, M. Fermeglia, S. Pricl, S. Miertus, E. Chiellini, Polymer 45 (2004) 8075-8083.

With the model built, It was time to optimize the cell, I tried the ClayFF force field version for Discover provided in this discussion forum, but I end up with the following error message:

INPUT FILES

___________


File Type          Name

---------          ----


Forcefield          C:\PROGRA~1\Accelrys\MATERI~2.0\share\Discover\res/clayff.frc

Molecular data          MMT.mdf

Coordinate          MMT.car


Space Group (C2/M)


Periodic Boundary Conditions

____________________________


Length (A)          Angle (degrees)

----------          ---------------


a  5.20000          alpha  90.00000

b  9.20000          beta   99.00000

c 10.13000          gamma  90.00000


Error: Energy expression: cannot find parameters for bond: O2(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Al(ao)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Al(ao)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: Si(st)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O1(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O2(ob)

Error: Energy expression: cannot find parameters for bond: Al(ao)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Al(ao)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Al(ao)-OH(oh)

Error: Energy expression: cannot find parameters for bond: O1(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: OH(oh)-Al(ao)

Error: Energy expression: cannot find parameters for bond: O2(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O2(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O2(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O2(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O2(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O2(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O2(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O2(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Al(ao)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Al(ao)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Al(ao)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Al(ao)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Al(ao)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Al(ao)

Error: Energy expression: cannot find parameters for bond: O3(ob)-Al(ao)

Error: Energy expression: cannot find parameters for bond: Si(st)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O1(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O2(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O1(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O2(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O2(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O1(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O2(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O2(ob)

Error: Energy expression: cannot find parameters for bond: Si(st)-O2(ob)

Error: Energy expression: cannot find parameters for bond: Al(ao)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Al(ao)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Al(ao)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Al(ao)-OH(oh)

Error: Energy expression: cannot find parameters for bond: Al(ao)-OH(oh)

Error: Energy expression: cannot find parameters for bond: Al(ao)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Al(ao)-O3(ob)

Error: Energy expression: cannot find parameters for bond: Al(ao)-OH(oh)

Error: Energy expression: cannot find parameters for bond: O1(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O1(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: O1(ob)-Si(st)

Error: Energy expression: cannot find parameters for bond: OH(oh)-Al(ao)

Error: Energy expression: cannot find parameters for bond: OH(oh)-Al(ao)

Error: Energy expression: cannot find parameters for bond: OH(oh)-Al(ao)

    while executing

"energy"

    invoked from within

"if {![\$ee exists Atom.Gradient]} {

    energy

  }"

    (procedure "vdWTailCorrection" line 55)

    invoked from within

"vdWTailCorrection 9.50"


Total time used by DISCOVER: 0.20 secs


Completion date: Fri Jan 11 15:04:28 2013

Exiting Discover: An ERROR has occurred!

I understand that the force field is not finding the parameters for those bonds.

How could I surpass that?

Should I try Forcite. My objective is to get the entry parameters for a mesoscale calculation of a MMT + Starch + plastiscizers system

Does anyone could know what I have done wrong?

Thank you very much for your time

Best regards

Felipe Azevedo