15min:

SIEGHARD ALBERT, KAREN KEPPLER ALBERT, SIGURD BAUERECKER AND MARTIN QUACK, Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland.

A complete understanding of the absorption behavior of the Earth's atmosphere and of the atmospheres of the giant planets (Saturn and Jupiter) and their moons (Titan) requires a detailed spectroscopic investigation of methanoid molecules over full atmospheric temperature ranges. For that reason we have interfaced a collisional and enclosive cooling cell based on White-type multireflection optics to our FTIR IFS125 HR prototype 2001 spectrometer\footnote S.~Albert, K.K. Albert, and M.~Quack, Trends in Optics and Photonics 84, 177 (2003). (MOPD=10~m). This cell makes it possible to record spectra at high spectral resolution in the temperature range 4-400~K with absorption path lengths up to 20~m. We have recorded the spectra of CH₄ and its isotopomers and of CHF₃, CHClF₂ and CHCl₂F^a between 2000 and 6000~cm^-1 in the temperature range 60-300~K. The spectra were recorded at resolutions ranging from 0.0015 to 0.004~cm^-1. We will present an analysis of the spectra of CHCl₂F in the 2 ₃ and 3 ₃ regions and an initial assignment of the resonance system 2 ₃/ ₃ + ₈/2 ₈ of CHClF₂. We discuss coincidences with CO₂ laser lines in the 2 ₃ region of the isotopic chiral molecule CH³⁵Cl³⁷ClF. Doppler-free quasi-resonantly enhanced ultra-high two-photon absorption experiments may be carried out in this region to study parity violation\footnoteM.~Quack, Angew.~Chem.~Intl.~Ed.~Engl. 114, 4812 (2002), M. Quack and J. Stohner, J.~Chem.~Phys. 119, 11228 (2003), R.~Berger, G.~Laubender, M.~Quack, A.~Sieben, J.~Stohner and M.~Willeke, Angew.~Chem.~Int.~Ed.~Eng. 44, 3623 (2005). in this molecule. In addition, we show CO nanoparticles recorded at 6~K .