Observation of nondispersing classical-like molecular rotation

TL;DR

This study demonstrates the creation and observation of classical-like and non-classical rotational wave packets in molecules using an optical centrifuge, revealing non-dispersing classical rotation in D2 molecules.

Contribution

It introduces a method to produce and distinguish between dispersing and non-dispersing rotational wave packets in molecules using an optical centrifuge.

Findings

Oxygen molecules show dispersive wave packet evolution with a transition in angular distribution shape.

Deuterium molecules exhibit non-dispersing, classical-like rotation.

The technique enables real-time tracking of molecular rotation states.

Abstract

Using the technique of an optical centrifuge, we produce rotational wave packets which evolve in time along either classical-like or non-classical trajectories. After releasing O2 and D2 molecules from the centrifuge, we track their field-free rotation by monitoring the molecular angular distribution with velocity map imaging. Due to the dispersion of the created rotational wave packets in oxygen, we observe a gradual transition between "dumbbell"-shaped and "cross"-shaped distributions, both rotating with a classical rotation frequency. In deuterium, a much narrower rotational wave packet is produced and shown to evolve in a truly classical non-dispersing fashion.