A Revised Radio-Frequency Spectrum for H2+

New calculations of the second order interaction $$d^{\prime\prime}$$ in the hyperfine structure of H ₂ + suggest that $$d^{\prime\prime}$$ is not negligible, contrary to the recent conclusion of Luke. Even for $$d^{\prime\prime} = 0,$$ Luke's results are incorrect, due to the neglect of state mixing. The calculations are related to the results of laboratory experiments and revised frequencies and transition probabilities are presented.