1. Universität Göttingen, Institut für Physikalische Chemie, Göttingen D-37077, Germany
2. Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, The Netherlands
3. CAS Center for Excellence in Quantum Information and Quantum Physics and Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, People’s Republic of China