Information about the spectral characteristics of the absorption bands of silicon tetrafluoride, SiF4, is of fundamental importance for the solution of many applied and scientific problems. Indeed, silicon tetrafluoride is a large-tonnage by-product formed in production various fluorine-containing substances. SiF4 has been also proposed as a remote terrestrial and Ios volcano monitoring probe. That is why the measurement of SiF4 content in out-door and in-door atmosphere is of great importance. FTIR spectroscopy of very strong ν3(SiF4) as well as other bands is very good suited to detect trace amounts of SiF4 in above mentioned and many other cases. However, experimental data about the electro-optical parameters of SiF4 molecule are incomplete.That is why the spectral characteristics of the SiF4 molecule in the range 3100-700 cm-1, including the absorption range of the band ν3, were studied in the gas phase at P=0,4-7 bar and in solutions in liquefied Ar and Kr. In the cryogenic solutions, the relative intensities of the vibrational bands, including the bands of isotopically substituted molecules, were determined. The absorption coefficients of the combination bands 2ν3, ν3+ ν1, ν3+ ν4, and 3ν4 are measured in the solution in Kr. In the gas phase of one component system at an elevated pressure of SiF4, the integrated absorption coefficient of the absorption band of the 28SiF4 molecule was measured to be A(ν3)=700±30 km/mol. Within the limits of experimental error, this absorption coefficient is consistent with estimates obtained from independent measurements and virtually coincides with a coefficient A(ν3)=691 km/mol calculated in this study by the quantum-chemical method MP2(full) with the basis set cc-pVQZ.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL1-Processes and interactions in the polar climate system