Spatial imaging of a novel type of molecular ions

TL;DR

This paper reports the discovery and imaging of a new type of molecular ion formed by Rydberg atoms, characterized by extremely long bond lengths and slow dynamics, opening avenues for studying advanced molecular physics.

Contribution

It introduces a novel molecular ion based on Rydberg atoms with micrometre-scale bonds, spatially imaging its structure and vibrational spectrum.

Findings

Observation of a new molecular ion type

Spatial resolution of bond length and orientation

Identification of slow molecular dynamics

Abstract

Atoms with a highly excited electron, called Rydberg atoms, can form unusual types of molecular bonds. The bond differs from the well known ionic and covalent bonds not only by its binding mechanism, but also by its bond length ranging up to several micrometres. Here, we observe a new type of molecular ion based on the interaction between the ionic charge and a flipping induced dipole of a Rydberg atom with a bond length of several micrometres. We measure the vibrational spectrum and spatially resolve the bond length and the angular alignment of the molecule using a high-resolution ion microscope. As a consequence of the large bond length, the molecular dynamics is extremely slow. These results pave the way for future studies of spatio-temporal effects in molecular dynamics, e.g., beyond Born-Oppenheimer physics.