Rotation-induced vibrational mixing in S1 H2CO near E′vib =2000–2300 cm−1: 2143 and 214161 levels

Coriolis-induced vibrational mixing in S1 H2CO near Evib =2000–2300 cm−1 is manifested by the rotational quantum number (J′,K′a) dependent variation of the emission intensity in the rotationally resolved, dispersed fluorescence spectrum. The c-axis Coriolis resonance between 2143 (Ka=5) and 214161 (K′a=4) is observed with ξ(c)st ≂0.2 cm−1. The b-axis Coriolis interaction between 214161 (Ka=5) and 4461 (K′a=4) in S1 as well as the a-axis Coriolis interaction between 42 and 4161 in S0 are observed. A significant degree of vibrational mixing is observed in the energy range, Evib =2000–2300 cm−1.