Rotational Structure of the Birge-Hopfield Bands of N₂

The 2–10, 3–11, 4–12, 5–13, 5–14, and 6–14 bands of the [Formula: see text] system in N 2 (Birge-Hopfield bands) have been photographed and measured. P, Q, and R branches are recorded and the indentification of the transition as 1 Π → 1 Σ is definitely confirmed. B′, B″, α′, and α″ values are presented.