Kinetic study of the reactions of ground-state silicon atoms, Si(3 3PJ), with buta-1,3-diene and but-2-yne
Abstract
We present a kinetic study of the reaction between atomic silicon in its electronic ground state, Si(3 3PJ), and the molecules buta-1,3-diene and but-2-yne. Si(3 3Pj) was generated by the repetitive, pulsed irradiation of SiCl4 in the presence of an excess of helium in a flow system kinetically equivalent to a static system, and monitored by time-resolved atomic resonance absorption spectroscopy at λ= 252 nm [Si(4 3PJ)â†� Si(3 3PJ)] using signal averaging. The following absolute second-order rate constants (300 K, errors 2σ) are reported: kR(buta-1,3-diene)= 1.1 ± 0.2 × 10–9 cm3 molecule–1 s–1, kR(but-2-yne)= 6.3 ± 0.9 × 10–10 cm3 molecule–1 s–1. These data, indicating reaction on every collision, are considered within the context of detailed work that has been described hitherto following the production of 31Si derived from nuclear recoil in the presence of buta-1,3-diene and involving ring formation, and in relation to the reaction of (CH3)2Si: with but-2-yne in steady pyrolysis investigations.