Details

Autor(en) / Beteiligte

• Pan, Huilin
• Liu, Kopin

Titel

Active stereo-control of the Cl + CH( = 1) reaction: a three-dimensional perspective

Ist Teil von

• Physical chemistry chemical physics : PCCP, 2020-05, Vol.22 (19), p.1949-1956

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The transition state in Cl + CH 4 is of Cl-H-C collinear geometry. As the reactant CH 4 is vibrationally excited by a linearly polarized infrared (IR) light to the antisymmetric-stretching state of ν 3 = 1, all four C-H bonds are collectively excited and any one of the H-atoms can be reactive. Yet, a strong alignment of the excited CH 4 ( ν 3 = 1), as evidenced from the striking stereo-specificity in the Cl + CH 4 reaction, was clearly revealed in a previous, exploratory study. Reported here is the full account of that investigation at two collisional energies of E c = 4.8 and 2.7 kcal mol −1 , using a crossed molecular-beam, product-imaging approach. By active control of the polarization direction of an IR laser under judiciously chosen beam-geometries, a complete set of polarization-dependent differential cross sections is disentangled from the CH 3 (0 0 ) product images. To our surprise, the quantitative results appear nearly identical to those obtained for the isotope-substituted reaction of Cl + CHD 3 ( ν 1 = 1) → HCl( ν ) + CD 3 (0 0 ). A detailed discussion is presented to elucidate the underlying physics for such an intriguing similarity in stereo-reactivity between a spherical-top and a symmetric-top reactant. Reactivity dependency on the collisional geometry in a reaction with a spherical-top reactant.