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Updated: May 16, 2026

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Hyperfine-resolved rovibrational and rotational spectroscopy of OH+ (X3Σ-)
Weslley G D P Silva1, Lea Schneider1, Urs U Graf1
1I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937, Köln, Germany. asvany@ph1.uni-koeln.de.
Abstract:
The OH+ (X3Σ-) radical cation has been investigated by combining a 4 K 22-pole ion trap apparatus with high-resolution IR and THz radiation sources. Applying different types of action spectroscopic methods, the fundamental vibrational band in the 3 µm range and the spin manifold of the N = 1 ← 0 rotational transition around 1 THz have been extended and refined. Additionally, the spin manifold of the N = 2 ← 1 rotational transition, scattered around 2 THz, has been measured for the first time with microwave accuracy. Although all hyperfine components of the pure rotational transitions are affected by considerable Zeeman splittings, a simulation of their contours allowed us to extract the field-free center frequencies with high accuracy. A global fit combining rovibrational and pure rotational transitions from the literature with those newly obtained in this work was performed, leading to improvements in the spectroscopic constants of OH+, particularly those in the ground vibrational state.
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