The Coulomb-Buckingham potential is an extension of the Buckingham potential for application to ionic systems. The formula for interaction is
LAMMPS
pair_coeff <i> <j> <A> <rho> <C> <cutoff_buckingham> <cutoff_coulumb>
rho > 0
[1] R.A. Buckingham. The Classical Equation of State of Gaseous Helium, Neon, and Argon. Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences 168, 264-283 (1938)
[2]