FORMATION OF SIF2 IN THE INFRARED MULTIPHOTON DECOMPOSITION OF SI2F6 AND THE REACTIONS OF SIF2 WITH BR-2, NO2 AND C2H4

The infrared multiphoton decomposition of Si2F6 has been investigated by time-resolved infrared diode laser spectroscopy. Direct formation o f SiF2 (X (1)A(1)) in the ground vibrational state and indirect format ion via vibrational relaxation were found. Simultaneous formation of S iF4 with SiF2 was also observed, indicating that a 1,2-fluorine shift occurs in preference to Si-Si bond scission. The vibrational relaxatio n of SiF2 in H-2 was found to be about twenty times faster than that i n N-2 because of resonant vibration-rotation energy transfer. The rate constants for the reactions of SiF2 with Br-2, NO2 and C2H4 were dete rmined as (7.6 +/- 1.0) X 10(-13), (5.8 +/- 0.9) x 10(-13) and < 1 X 1 0(-15) cm(3) molecule(-1) s(-1), respectively, at room temperature.