Graded homework problem #1.

The sun's atmosphere contains vast quantities of He⁺ cations. These ions absorb some of the sun's thermal energy, promoting electrons from the He⁺ ground state to various excited states. The energy of these excited states are called excitation energies and are measured relative to the ground state whose excitation energy is zero by definition. A He⁺ ion in the fifth energy level may return to the ground state by emitting three successive photons: an infrared (IR) photon (wavelength = 1014 nm), a green photon (469 nm), and an X-ray (26 nm).

(a) Calculate the excitation energies for each of the levels occupied by the He⁺ ion as it returns to the ground state.

(b) Draw an energy level diagram for He+ cations that illustrates all the details of this cascade process.