부산대학교 도서관

Ratecoefficients for the CH3+ CH3reaction,over the temperature range 300–900 K, have been corrected forerrors in the absorption coefficients used in the original publication(Slagleet al., J. Phys. Chem.1988, 92, 2455−2462). These corrections necessitated the developmentof a detailed model of the B̃2A1′(3s)–X̃2A2″ transition inCH3and its validation against both low temperature andhigh temperature experimental absorption cross sections. A masterequation (ME) model was developed, using a local linearization ofthe second-order decay, which allows the use of standard matrix diagonalizationmethods for the determination of the rate coefficients for CH3+ CH3. The ME model utilized inverse Laplace transformationto link the microcanonical rate constants for dissociation of C2H6to the limiting high pressure rate coefficientfor association, k∞(T); it was used to fit the experimental rate coefficients using theLevenberg–Marquardt algorithm to minimize χ2calculated from the differences between experimental and calculatedrate coefficients. Parameters for both k∞(T) and for energy transfer ⟨ΔE⟩down(T) were variedand optimized in the fitting procedure. A wide range of experimentaldata were fitted, covering the temperature range 300–2000 K.A high pressure limit of k∞(T) = 5.76 × 10–11(T/298 K)−0.34cm3molecule–1s–1was obtained, which agrees well with the bestavailable theoretical expression. [ABSTRACT FROM AUTHOR]