Far-infrared spectroscopy of heavy protonated noble gas species using synchrotron radiation

ABSTRACT

In this work, we report new absorption spectra of protonated noble gas species ArH${}^{+}$, KrH${}^{+}$ and XeH${}^{+}$. Both pure rotation transitions and rotation-vibration transitions were recorded at high resolution using the Fourier transform interferometer of the AILES beamline of the synchrotron facility SOLEIL. The species were produced in a ‘hollow cathode’ discharge cell for which the cathode is cooled down to liquid nitrogen temperature. While our spectra of ArH${}^{+}$ do not provide new experimental information compared to the wealth of data available in the literature, both spectra of KrH${}^{+}$ and XeH${}^{+}$ contain numerous new transitions belonging to several isotopologues observed in natural abundance. KrH${}^{+}$ and XeH${}^{+}$ spectra have been analysed using a Dunham Hamiltonian to provide mass independent sets of parameters and allowing to determine bond lengths with improved accuracy.

GRAPHICAL ABSTRACT

Keywords:

• Astrochemistry
• far-infrared
• synchrotron radiation
• protonated noble gas
• Fourier-transform rotation spectroscopy

Acknowledgments

The authors are very grateful to M.-A. Martin-Drumel for her careful reading of the paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Programme National ‘Physique et Chimie du Milieu Interstellaire’ (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES.