Photoionization of a diatomic molecule produces a singly charged cation. For the molecules listed here, calculate the bond order of the neutral molecule and the lowest energy cation. For which of the molecules do you expect the n = 0 → n′ = 1 vibrational peak to have a higher intensity than the n = 0 → n′ = 0 vibrational peak? The term n refers to the vibrational quantum number in the ground state, and n′ refers to the vibrational quantum number in the excited state.

a. H₂

b. O₂

c. F₂

d. NO