Vibrationally-resolved core-excitation spectroscopy of (near-)symmetric diatomic molecular ions

• Applicants: Dr. Pierre-Michel Hillenbrand; Professor Dr. Stefan Schippers
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 536103037

The proposed project aims at performing vibrationally resolved core-excitation spectroscopy of symmetric and near-symmetric molecular ions, specifically C2+, CN+, N2+, CO+, NO+, and O2+. We will experimentally determine the spectroscopic constants of core-excited levels, defined as electronic states with a K-shell vacancy. Our results will serve as valuable benchmark data to guide the development of accurate theoretical descriptions of core-excited diatomic molecules. While core-excitation spectroscopy of neutral molecules is routinely performed at synchrotron radiation facilities, experiments with molecular ions require to overcome additional technical challenges. To this end we will establish a new experimental approach which combines our existing merged-beams apparatus – installed at the synchrotron radiation facility PETRA III – with a new position sensitive detector for molecular fragments. By combing measurement on diatomic molecular ions, diatomic neutral molecules, and few-electron atomic ions, we aim to reduce calibration errors substantially and thus achieve an unsurpassed level of accuracy for the investigated spectroscopic constants.

• DFG Programme: Research Grants