Please reply to the list, not to me …
There is no equation -> potential option in LAMMPS.
Would be really inefficient I think. That’s really
what pair table is for. If you want to play with
alternate eqs via tabulation you could. My guess
is what is going wrong with your tabulation is
the extreme range it spans and how quickly it
varies (as a function of r). Softer tabulations
might spline better and be more than adequate
for your model. E.g. just trimming off the tiny r
values that are so large might help it spline better.