title: The dynamics of reaction of Cl atoms with tetramethylsilane.
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' approximately 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.
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, Bristol, UK BS8 1TS.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Retail
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Rose
authors.forename: Julie K
authors.initials: JK
authors.lastname: Pearce
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Greaves
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Orr-Ewing
mesh_terms: D000465:Algorithms; D016880:Anisotropy; D002713:Chlorine / Q000737:chemistry* / Q000528:radiation effects; D004980:Ethane / Q000737:chemistry; D006851:Hydrochloric Acid / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D008958:Models, Molecular; D010782:Photolysis; D014297:Trimethylsilyl Compounds / Q000737:chemistry*
chemical_list: D014297:Trimethylsilyl Compounds; C073196:tetramethylsilane; D002713:Chlorine; D004980:Ethane; D006851:Hydrochloric Acid