The lennard-jones potential is widely-used to describe van der waals interactions. it has the form: v(r) = 4e s r 12 s r 6 where s and e are constants that vary with the atoms involved. s has units of length, and e has units of energy. (a) differentiate this and set the derivative to zero in order to find the equilibrium bond length and bond energy in terms of s and e. (b) for interactions between argon atoms, e = 1: j, and s = 0: 3345 nm. in solid argon, each atom interacts with 12 nearest neighbors at the equilibrium bond distance. use this information to estimate the total cohesive (that is, bonding) energy in 1 mole of solid argon.