We have evaluated the ground-state wavefunction of hydrogen in Eq. (9.48), and in this example, we will construct the first excited state n = 2, ℓ,m = 0 wavefunction. This can then be used, along with the components of the Laplace–

Runge–Lenz vector, to construct all wavefunctions with the same energy, which you will explore in Exercise 9.5.