Knowledge Bank

We report the pure rotation spectrum of HN$\mathrm{2+}$ measured by Fourier Transform (FT) absorption spectroscopy in the 20-40 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ spectral range. The cations are produced in a liquid nitrogen cooled hollow cathode discharge cell developed on the AILES beamline of synchrotron SOLEIL. The set-up was optimized by recording rotation-vibration spectra of H$\mathrm{3+}$($\nu 2$ band centered at 2521 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$), HN$\mathrm{2+}$ ($\nu 1$ band centered at 3234 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$) and HCO$+$($\nu 1$ band centered at 3089 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$). Many rotation-vibration lines have been assigned for each ion and 5 pure rotational transitions have been detected for HN$\mathrm{2+}$. These results demonstrate the feasibility to record far-infrared (far-IR) spectra of cationic species using FT broad band spectroscopy associated to the bright synchrotron radiation continuum as an alternative to laser-based frequency tunable techniques. In the presentation, we will describe the experimental set-up, the results obtained and the perspectives of this preliminary work which will rely on the exploitation of intense Coherent Synchrotron Radiation (CSR).