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Updated: May 18, 2026
10:40
High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Visible transitions from ground state H3+ measured with high-sensitivity action spectroscopy
Max Berg1, Andreas Wolf, Annemieke Petrignani
1Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
Summary
Researchers observed new spectral lines for cold hydrogen ions (H3+) in the visible spectrum. These ultra-weak transitions provide crucial benchmarks for theoretical calculations, advancing spectroscopy towards the dissociation limit.
Area of Science:
- Molecular Spectroscopy
- Quantum Chemistry
- Astrophysics
Background:
- Hydrogen ions (H3+) are fundamental molecules in various astrophysical environments.
- Accurate spectroscopic data for H3+ is crucial for understanding molecular processes in space.
- Previous studies focused on near-infrared transitions, leaving the visible spectrum largely unexplored.
Purpose of the Study:
- To observe and characterize new spectral lines of cold H3+ ions in the visible region.
- To extend the measured spectral range of H3+ towards its dissociation limit.
- To provide experimental benchmarks for ab initio calculations of H3+ spectroscopy.
Main Methods:
- Utilized a cryogenic 22-pole ion trap to cool H3+ ions.
- Employed highly sensitive action spectroscopy with laser-induced chemical reactions.
- Detected ArH+ ions with single-ion sensitivity to identify H3+ transitions.
Main Results:
- Observed new, extremely weak H3+ spectral lines in the visible region.
- Measured transitions involving up to eight vibrational quanta, reaching 16,700 cm(-1).
- Achieved spectroscopic accuracy of 0.1 cm(-1) with ab initio calculations, validated by experimental data.
Conclusions:
- The observed visible transitions significantly extend the known spectrum of H3+.
- These findings enable further development of theoretical models and pave the way for exploring transitions closer to the dissociation limit.
- The high accuracy of predictions and measurements will aid in identifying H3+ in diverse environments.
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