15min:

O. PIRALI, S. GRUE, M. VERVLOET, Ligne AILES, Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin, 91192 Gif sur Yvette Cedex - France.

We report the pure rotation spectrum of HN₂⁺ measured by Fourier Transform (FT) absorption spectroscopy in the 20-40 cm^-1 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 H₃⁺( ₂ band centered at 2521 cm^-1), HN₂⁺ ( ₁ band centered at 3234 cm^-1) and HCO⁺( ₁ band centered at 3089 cm^-1). Many rotation-vibration lines have been assigned for each ion and 5 pure rotational transitions have been detected for HN₂⁺. 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).