No abstract

The infrared multiple photon decomposition of hexafluorodisilane has been studied with a C02 TEA laser with the intention of silicon isotope separation. The products were SiF4 (55% in silicon balance), a trace of Si3F8, and a whitish film. SiF4 was found to be considerably enriched with "Si in the decomposition at P(6)-P(20) lines of the 10.6-/um C02 band. Product yields and enrichment factors were examined as functions of irradiation wavenumber, laser fluence, and Si2F6 pressure.Decomposition occurred at a fluence as low as 0.15 J cm"1 2 3.The isotope content of "Si in SiF4 was nearly 50%, for example, in the irradiation of 2 Torr of natural Si2F6 with laser radiation at 951.19 cm'1 and 0.25 J cm"2. On the basis of the observed results, large-scale separation of "Si was carried out by using a flow system and a high-repetition laser. SiF4 with a "Si content of 33% was produced at a rate of 1.47 g/h.

The irradiation of Si2F6 with CO2 TEA laser pulses induces highly efficient decomposition yielding SiF4 as the main product, traces of Si3F8 and a whitish film.