HIGH-RESOLUTION INFRARED SPECTRA AND ANALYSES OF SiF4

Wavenumber / cm -1 28 SiF4 Q branch Volcanoes reject large amounts of sulfurcontaining gases in the atmosphere; these represent 10 to 15 % of the anthropogenic sulfur emissions. Thermodynamic considerations show that silicon tetrafluoride (SiF4) should be a normal trace component of volcanic gases. Some studies report that the possible importance of SiF4 had been neglected because of the problems of reporting HF and SiF4 separately in conventional analyses. However, a better knowledge of spectroscopic parameters is needed for this molecule in order to derive accurate concentrations. This is why we undertook an extensive high-resolution study of its infrared absorption bands, including the fundamentals and several overtone and combinations. We present here a detailed analysis and modeling of the strongly absorbing ν3 fundamental, for the three isotopologues in natural abundance: 28SiF4 (92.23 %), 29SiF4 (4.67 %) and 30SiF4 (3.10 %). Progresses in the analysis of the other bands will be outlined.