Difficulty in modeling water molecules(TIP3P) with polymer(COMPASS)

[Tushita_Rohilla]

Thanks for your suggestion.
I could not find cross-term parameters as part of TIP3P model but came across this page -

How to set the COMPASS class2 potential parameter for water?

Dear lammps-users, I’m now calculating the dielectric constant of water via lammps, which the flexible water potentials are better suited. The attached paper(http://journals.aps.org/prb/abstract/10.1103/PhysRevB.31.2643) by K. Toukan and A. Rahman is really a good flexible spc water model, which introducing an anharmonic Morse potential for the O-H stretch vibrational part, so that I want to use this model. According to the equ(3) from the above mentioned paper, I checked the lammps website an…

This page provides Bond Bond and Bond Angle Coeffs but as part of class2 forcefield.

Only for trial, I added these parameters to the data file to see its effect on the simulation. The error that I was facing was removed. But this doesn’t solve the problem as these are not part of TIP3P according to which other parameters are provided.

Here are the lines from the data file:

**Angle Coeffs # class2

1 class2 107.66 39.641 -12.922 -2.42999
2 class2 110.77 41.453 -10.604 5.129
3 class2 112.67 39.516 -7.443 -9.5583
4 harmonic 55.0 104.52

BondBond Coeffs

1 class2 5.3316 1.101 1.101
2 class2 3.3872 1.53 1.101
3 class2 0 1.53 1.53
#4 class2 2.4139579349904396e-23 1.0 1.0

BondAngle Coeffs

1 class2 18.103 18.103 1.101 1.101
2 class2 20.754 11.421 1.53 1.101
3 class2 8.016 8.016 1.53 1.53
#4 class2 0.228 0.228 1.0 1.0
**

Kindly suggest.

Thanks