Rotational line strengths in 3Σ+–3Σ− electronic transitions. The β3Σu+ – X3Σg− and A3Σu+ – X3Σg− systems of molecular oxygen

Abstract

Rotational line strengths are given for ³Σ⁺(int) – ³Σ⁻(int) transitions arising from spin–orbit coupling. Observed branch intensities for the forbidden β³Σ_u⁺ – X³Σ_g⁻ transition of O₂ may be explained by assuming spin–orbit mixing of β³Σ_u⁺ with the B³Σ_u⁻ and E³Σ_u⁻ states. On the other hand, observed branch intensities for the Herzberg I A³Σ_u⁺ – X³Σ_g⁻ transition of O₂ may be explained only by assuming mixing with ³Σ and ³Π states. In neither case do earlier formulae, derived assuming a single ³Π perturber, apply.