The dynamics of reaction of Cl atoms with tetramethylsilane

Bertrand Retail, Rebecca A. Rose, Julie K. Pearce, Stuart J Greaves, Andrew J. Orr-Ewing

Research output: Contribution to journalArticle

Abstract

Rotational state distributions and state-selected CM-frame angular distributions were measured for HCl (v' = 0, j') products from the reaction of Cl-atoms with tetramethylsilane (TMS) under single collision conditions at a collision energy, E-coll, of 8.2 +/- 2.0 kcal mol(-1). The internal excitation of these products was very low with only 2% of the total energy available partitioned into HCl rotation. A transition state with a quasi-linear C-H-Cl moiety structure was computed and used to explain this finding. A backward peaking differential cross section was also reported together with a product translational energy (T') distribution with a maximum at T' similar to E-coll. This scattering behaviour is accounted for by reactions proceeding through a tight transition state on a highly skewed potential energy surface, which favours collisions at low impact parameters with a strong kinematic constraint on the internal excitation of the products. The large Arrhenius pre-exponential factor previously reported for this reaction is reconciled with the tight differential scattering observed in our study by considering the large size of the TMS molecule.

Original languageEnglish
Pages (from-to)1675-1680
Number of pages6
JournalPhysical Chemistry Chemical Physics
Volume10
Issue number12
DOIs
Publication statusPublished - 2008

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