The manifestations of 'l-Doubling' in gas-phase rotational dynamics

The 'l-Doubling' phenomenon emanates from the coupling between molecular rotations and perpendicular vibrations (bending modes) in polyatomic molecules. This elusive phenomenon has been largely discarded in laser-induced molecular alignment. Here we explore and unveil the ramifications of 'l-Doubling' to the coherent rotational dynamics of triatomic molecules at ambient temperatures and above. The observed 'l-Doubling' dynamics may be wrongly considered as collisional decay throughout the first few hundreds of picoseconds past excitation, highlighting the importance of correct assimilation of l-Doubling in current research of dissipative rotational dynamics and in coherent rotational dynamics in general.