First analysis of the high resolution FTIR spectrum of the ν₂ band of the FCO₂ radical at 970.2 cm⁻¹

Abstract

The infrared spectrum of the fluorocarboxyl radical, FCO₂, was recorded at high resolution (0.0035 cm⁻¹) in the 600–1400 cm⁻¹ region on a Bruker IFS 120 HR Fourier transform spectrometer of the University of Wuppertal. The analysis of the A-type ν₂ band of FCO₂ (CF stretching mode) centred at 970.208 cm⁻¹ was performed making use of the ground state parameters achieved by [L. Kolesniková, J. Varga, H. Beckers, M. Šimečková, Z. Zelinger, L. Nová Stříteská, P. Kania, H. Willner, and Š. Urban, J. Chem. Phys. 128, 224302/1 (2008)]. For the FCO₂ radical, the ν₂ transitions are, in principle, split into two spin–rotation subcomponents corresponding to J = N ±1/2. However the spin–rotation parameters in the 2¹ vibrational state have values similar to those of the ground state, and spin–rotation doublings are observable only for the weaker transitions involving medium K_a or K_c values in the P and R branches. The ν₂ fundamental band is weakly perturbed by the 2ν₅ dark overtone band at 965.4 cm⁻¹ and the 2¹ and 5² energy levels of FCO₂ are coupled through Fermi type resonances. The final energy level calculation was performed accounting both for the spin–rotation interaction within the 2¹ and 5² vibrational states, and the 2¹ ⇔ 5² Fermi-type resonances.

Keywords:

• fluoroformyloxyl radical
• high resolution IR spectrum
• rotational analysis
• spin–rotation interactions
• Fermi resonances

Acknowledgements

A.P. is grateful to the INSU (Institut national des sciences de l'Univers) of the CNRS for financial support. M.S. is grateful to the three months post-doc position of the ‘European Science Foundation’ through the ‘Interdisciplinary Tropospheric Research: from the Laboratory to Global Change’ (INTROP) Project. We appreciate support from the Deutsche Akademische Austauschdienst (DAAD, PPP-Tschechien, D22-CZ 12/09-10) for the German–Czech collaboration, for support from MEYS of the Czech Republic provided via Research program LC06071 and a grant OC09050 (action COST ES0604) and H.B. and H.W. acknowledge financial support from the Deutsche Forschungsgemeinschaft (DFG).