For my condensed matter physics class, please add explanation to solution! Thank-you

02 (10 points) Consider a one-dimensional crystal chain of alternating charged ions of charge iq. Assume that the distance between nearest neighbors is R. Assume that, in addition to the long-range Coulomb interaction between the charges, there is a nearest-neighbor repulsive potential of the form Vrep(R) = % with A > 0. a) [2 marks] Derive an expression for the total energy of the crystal for an arbitrary R. b) [2 marks] Find the equilibrium nearest-neighbor distance R0