J. Phys. Chem. Lett. 11, 5199–5203 (2020)

Rotationally Resolved Excitation Spectra Measured by Slow Electron Detachment from Si₂^–

Shimpei Iida^3,*, Susumu Kuma¹, Jun Matsumoto², Takeshi Furukawa³, Hajime Tanuma³, Toshiyuki Azuma^1,3, Haruo Shiromaru², Vitali Zhaunerchyk⁴, and Klavs Hansen^5,6

1 Atomic, Molecular and Optical Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan

2 Department of Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan

3 Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan

4 Department of Physics, University of Gothenburg, 41296 Gothenburg, Sweden

5 Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin 300350, China

6 School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China

* s-iida@tmu.ac.jp

Abstract

Laser-induced delayed electron detachment from Si₂^– stored in an electrostatic ion storage ring was observed on the 10 microsecond time scale. The excitation spectra for photon energies near threshold show well-resolved multipeak structures, which are attributed to rovibronic transitions to the electronic excited state. This structure appears only in the signal measured with the delay. The occurrence of delayed detachment on such a long time scale is unusual for diatomic molecules, suggesting that both the autodetachment and fluorescence are slow.