Rydberg trimers and excited dimers bound by internal quantum reflection

TL;DR

This paper explores how quantum reflection can create ultralong-range Rydberg molecules, revealing new binding mechanisms and molecular states at large interatomic distances, advancing ultracold chemistry understanding.

Contribution

It identifies novel Rydberg molecular states formed through internal quantum reflection, a mechanism previously unexplored in ultracold molecular chemistry.

Findings

Discovery of bound triatomic Rydberg molecules involving quantum reflection.

Identification of excited dimer states bound by internal quantum reflection.

Experimental evidence of ultralong-range Rydberg molecules.

Abstract

Quantum reflection is a pure wave phenomena that predicts reflection of a particle at a changing potential for cases where complete transmission occurs classically. For a chemical bond, we find that this effect can lead to non-classical vibrational turning points and bound states at extremely large interatomic distances. Only recently has the existence of such ultralong-range Rydberg molecules been demonstrated experimentally. Here, we identify a broad range of molecular lines, most of which are shown to originate from two different novel sources: a single-photon associated triatomic molecule formed by a Rydberg atom and two ground state atoms and a series of excited dimer states that are bound by a so far unexplored mechanism based on internal quantum reflection at a steep potential drop. The properties of the Rydberg molecules identified in this work qualify them as prototypes for a new type of chemistry at ultracold temperatures.