Suppose | n l ⟩ ⟩ is an eigenvector of the Hamiltonian, where l is the angular momentum, and n represents the energy, so L 2 | n l ⟩ ⟩ = l ( l + 1 ) ℏ ℏ 2 | n l ⟩ ⟩ , and we may label the Hamiltonian as H l : H l = 1 2 μ μ [ p r 2 + 1 r 2 l ( l + 1 ) ℏ ℏ 2 ] + V ( r ) .