Consider an ##H_2## molecule where the protons are separated by a wide
distance R and both are located on the z-axis. Ignoring the spin degrees
of freedom and treating the dipole-dipole interaction as a perturbation,
use perturbation theory to estimate an upper limit for the ground state
energy of this molecule.
The Attempt at a Solution
What I think is that since hydrogen molecule has 0 dipole moment there should be no perturbation to calculate.