Since B and N are not charged atoms as I specified in my data file, I should
not have coulombic interactions involving B and N atoms and only LJ should
be employed between O-B and 0-N. I expect from lj/cut/coul/long to do this
as I assigned the charges of B and N as 0 already. So I did not need to
define anything between H-B and H-N since there is no LJ between them in
addition the absence of Coulomb.

i don't understand what you are saying here. you are telling us that
you get a more realistic model, if there are no interactions between
the water and the BN at all? how is this possible? how do you
determined what is realistic?

i can only point out the obvious mistakes. for anything else, you have
to provide *much* more information, but then again, this seems to be
more a question of the science rather than how to implement it with
LAMMPS, so chances that somebody can do more than looking for obvious
mistakes are small.

I corrected the mistake between H and O but there is no significant change
son I think the actual problem is the interactions between O-B and O-N
because I get more consistent results without those cross-relations(O-B,
O-N). But this is still not acceptable as we expect, because potential
between 0-B and O-N must be important.

May be LJ parameters are not appropriate for simulating B-N what do you
think? I had to try this because there is no way to combine Tersoff and LJ

it doesn't matter what i think. this is not my field of science and i
don't even want to think about it.

for cross relations, right?

well, at that point, the question is: what is the origin of your O-B
and O-N parameters and the reason you don't have H-N and H-B. after
all, for a system like this, you would have to look those up from a
suitable publication or - failing that - parameterize them yourself.