Observation of a molecular bond between ions and Rydberg atoms

Atoms with a highly excited electron, called Rydberg atoms, can form unusual types of molecular bonds(1-4). The bonds differ from the well-known ionic and covalent bonds(5,6) not only by their binding mechanisms, but also by their bond lengths 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(7). 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 (for example, beyond Born-Oppenheimer physics).

Automated summary

Researchers have discovered a new type of molecular ion based on the interaction between the ionic charge and a flipping-induced dipole of a highly excited electron, called Rydberg atom. This molecular ion has a bond length of several micrometres. Using a high-resolution ion microscope, they have measured the vibrational spectrum and spatially resolved the bond length and angular alignment of the molecule. Due to the large bond length, the molecular dynamics are extremely slow.