Coriolis-induced intensity perturbations in the rotationally resolved fluorescence spectra from the 51 and 1141 eigenstates of H2CO(Ã 1A2): Vibrational mixing near E′vib =3000 cm−1

Abstract

It has been found in the rotationally resolved fluorescence emission of the 5¹ and 1¹4¹ levels of S₁ H₂CO that the rotational line intensity distributions of various vibronic bands are very unusual. This is due to the Coriolis interaction between the zero‐order 5¹ and 1¹4¹ rotational levels and also the interaction between these and other neighboring levels. The theory of the rotational intensity bias and borrowing based on the rotation‐induced vibrational mixing is used to explain the intensity anomaly as well as the variation in the mixing coefficients with the variation in the rotational quantum numbers, J’ and K_a. For most of the rotational levels populated at room temperature, the Coriolis‐induced vibrational mixing of 5¹ and 1¹4¹ appears nearly complete.