Observation of pendular butterfly Rydberg molecules.

Thomas Niederprüm,Tanita Eichert,Oliver Thomas,Jesús Pérez-Ríos,Carsten Lippe,Herwig Ott,Chris H Greene

doi:10.1038/ncomms12820

Abstract

Engineering molecules with a tunable bond length and defined quantum states lies at the heart of quantum chemistry. The unconventional binding mechanism of Rydberg molecules makes them a promising candidate to implement such tunable molecules. A very peculiar type of Rydberg molecules are the so-called butterfly molecules, which are bound by a shape resonance in the electron–perturber scattering. Here we report the observation of these exotic molecules and employ their exceptional properties to engineer their bond length, vibrational state, angular momentum and orientation in a small electric field. Combining the variable bond length with their giant dipole moment of several hundred Debye, we observe counter-intuitive molecules which locate the average electron position beyond the internuclear distance.

Highlights

Obtaining full control over the internal and external quantum states of molecules is the central goal of ultracold chemistry [9] and allows for the study of coherent molecular dynamics, collisions [15, 17, 23, 24] and tests of fundamental laws of physics [4]
The interaction with the ground state atom can substantially displace the electron from the ionic core, giving rise to permanent electric dipole moments up to one kiloDebye [8]
Rydberg molecules are dominated by the pwave scattering between the Rydberg electron and the ground state atom, which maximizes the gradient of the electron wave function at the position of the ground state atom

Summary

Introduction

Obtaining full control over the internal and external quantum states of molecules is the central goal of ultracold chemistry [9] and allows for the study of coherent molecular dynamics, collisions [15, 17, 23, 24] and tests of fundamental laws of physics [4]. The interaction with the ground state atom can substantially displace the electron from the ionic core, giving rise to permanent electric dipole moments up to one kiloDebye [8].

Results

Conclusion