THE MECHANISM OF LINEAR AND SQUARE CHAIN-BRANCHING AND THE ROLE OF HO2 RADICALS IN CHAIN COMBUSTION OF SIH4 WITH O2

Hydrogen peroxide (H2O2) is identified for the first time among the ox idation products of SiH4 with O2 at pressures below 300 Pa and tempera tures below 310 K. The H2O2 concentration is found to increase either with an increase in the silane concentration in the starting mixture o r with a decrease in the specific surface area (S/V) of a reaction ves sel. It is shown that H2O2 is formed by bimolecular reactions involvin g the HO2 radical. A profound inhibiting effect of water vapors is rev ealed near the first self-ignition limit of the SiH4-O2 mixture. On th e basis of previously reported experimental data and the obtained resu lts, a reaction scheme is proposed for chain branching involving activ e particles, along with the reaction of square branching.