(IMAGE) Physikalisch-Technische Bundesanstalt (PTB) Caption This is the basic concept of the experiment: MgH+ (orange) and Mg+ (green) are trapped together in a linear ion trap. The two-ion compound is cooled to the motional ground state via the atomic ion. An oscillating dipole force changes the motional state according to the rotational state of the molecular ion. This motional excitation can be detected on the atomic ion. Credit (Fig.: PTB) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.