Strong polarity membrane simulation

Dear all,

My simulation box is like a adsorption of water by using inorganic membrane like zeolite. I have tried several models simulation the dynamics by LAMMPS. For those with not very strong polarity of the membrane ( Al/Si=0 or 0.6 O=-0.21 or -0.4), it works well. While for those with strong polarity (Al/Si=1.5, O=1.3), it collapses at very first few steps. ( with the error of "out of range” or “missing bonds” or “missing atoms”)

My method is tethering those membrane atoms and make the water molecules moving freely. I use lj/cut/coul/long as pair style for whole system and using the SPC/E potential for water.

I tried to shrink the tilmestep, but it did not work. When I turn off the coul interaction, the system could run well. Can anyone tell me is the algorithm i using is wrong or those parameters are wrong. I tried ewald and pppm both, but neither worked. The parameters are proved to work in others’ essays. So i do not think they are wrong. But they are using a combination of buckinghum and lj as the potential model. Could that be the problem? And if I want to do simulation in my own method, is there a way to fix the problem?

Best wishes,