Formation of SiF2 in the infrared multiphoton decomposition of Si2F6 and the reactions of SiF2 with Br2, NO2 and C2H4

The infrared multiphoton decomposition of Si2F6 has been investigated by time-resolved infrared diode laser spectroscopy. Direct formation of SiF2 (X̃1A1) in the ground vibrational state and indirect formation via vibrational relaxation were found. Simultaneous formation of SiF4 with SiF2 was also observed, indicating that a 1,2-fluorine shift occures in preference to SiSi bond scission. The vibrational relaxation of SiF2 in H2 was found to be about twenty times faster than that in N2 because of resonant vibration-rotation energy transfer. The rate constants for the reactions of SiF2 with Br2, NO2 and C2H4 were determined as (7.6 ± 1.0) × 10−13, (5.8 ± 0.9) × 10−13 and < 1 × 10−15 cm3 molecule−1s−1, respectively, at room temperature.