Rephasing of Collisionless Molecular Rotational Coherence in Large Molecules

We present experimental results on the rephasing of collisionless rotational coherence in jet-cooled trans-stitbene. The results represent the first observation of quantum coherence effects arising from the rotational level structure of molecules. We discuss the nature of the effect, its possible influence in time-resolved polarization experiments designed to probe intramolecular energy flow, and its possible uses as a new spectroscopic tool.