How to modify interaction potential in Lammps

Dear Sir,

I want to study aqueous Uranyl(VI) cation using Lammps, In which I want to use the potential -

U= epsilon*{(sigma/r)^12} - 2epsilon{(sigma/r)^6}

while the used potential by pair_style : lj/cut/coul/long ( In Lammps) is -

U= epsilon*{(sigma/r)^12} - epsilon*{(sigma/r)^6}

Can i modify the potential used in Lammps code and if i modify the source code then i have to recompile only that program file ( pair_lj_cut_coul_long.cpp) or i have to recompile complete Lammps?

Thanking You,

With Regards,

Pooja Sahu

The two potentials are essentially the same.

You can solve equations like:
e1 * s1^12 = e2 * s2^12
2 * e1 * s1^6 = e2 * s2^6

Francis