Rovibronic emission locked fluorescence excitation spectroscopy. A selective probe for coriolis perturbation in rovibronic levels of S₁ H₂CO

The fluorescence excitation spectrum of the H₂CO S₁ ← S₀ transition in the 2₀¹4₀³ region has been taken with the fluorescence band locked onto a specific rovibronic emission feature. This is a very useful spectroscopic probe of Coriolis perturbation. It permitted the assignment of a new vibronic transition, 2₀¹4₀¹6₀¹, which overlaps with the stronger vibronic transition, 2₀¹4₀³, and borrows intensity through b-axis Coriolis coupling with 2¹6¹.