Kinetic studies of the reactions of atomic chlorine and bromine with silane

Abstract

The kinetics of the reactions CI(zPJ) + SiH4 (1) and Br(ZPJ) + SiH4 (2) have been investigated by time-resolved atomic resonance fluorescence spectroscopy. Halogen atoms were generated by flash photolysis of CCl, and CH2Br2. Experiments over 295-472 K yielded kl = (1.56 f 0.1 1) X exp[(2.0 f 0.2) kJ mol-'/Rq cm3 s-I and studies over 295-575 K yielded k2 = (9.0 f 1.5) X lo-" exp[(-17.0 f 0.6) kJ mol-'/Rq cm3 s-I. 95% confidence intervals are about f10% and f20%, respectively. These expressions are in good agreement with most earlier measurements. An expression for k-' is also derived. Alternative interpretations of the negative activation energy for k , , based on transition-state theory or formation of an intermediate adduct, are discussed.

Enthalpy of Formation of the Cyclohexadienyl Radical and the C−H Bond Enthalpy of 1,4-Cyclohexadiene: An Experimental and Computational Re-Evaluation

“…[43][44][45][46] The photochemical reactor is a stainless steel six-way cross heated within an oven. Gas temperatures T in the reaction zone, where the arms of the reactor (i.d. )…”

Kinetics and thermochemistry of the addition of atomic chlorine to acetylene

“…The fluorescence signal is proportional to [Cl], plus a steady background from scattered light within the reactor. Details of the apparatus and technique have been given elsewhere [19,20]. Experimental parameters such as [CCl 4 ] and the photolysis energy F, together with the beam cross section of approximately 7 x 8 mm 2 and the absorption cross-section of CCl 4 [21], were employed to estimate the initial atomic concentration [Cl] 0 .…”

Kinetic and modeling studies of the reaction S+H2S

“…The laser photolysis apparatus and general operating procedures have been described elsewhere [10][11][12][13]. Briefly, mixtures of H2S and CS2 diluted in Ar bath gas flowed slowly through a heated, stainless steel reaction cell.…”