10min:

ROBERT J. HOLIDAY, CHAN HO KWON, CHRISTOPHER J. ANNESLEY AND F. FLEMING CRIM, Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706.

Product state distributions for the reaction of vibrationally state selected CH₃D with Cl, CH₃D( )~+~Cl~ ~CH₂D~+~HCl, reveal the extent to which vibrational energy initially deposited in the reactant survives in the CH₂D product. Infrared excitation prepares CH₃D in either the ₁~+~ ₄ (E) or the 2 ₄ (A₁, E) C-H stretching states and resonant enhanced multiphoton ionization (REMPI) detects the CH₂D. With ₁ + ₄ excitation, the reaction forms only vibrationally unexcited products, CH₂D (0₀), but 2 ₄ excitation forms CH₂D with stretch excited (1₁) and stretch-bend combination excited (1₁4₁) products. These results are consistent with the spectator model. In local mode notation, the ₁ + ₄ state corresponds to two quanta of excitation in the C-H bond (|200>|0>), and it reacts at the excited bond, giving all ground state CH₂D. The 2 ₄ state corresponds to excitation in two C-H bonds (|110>|0>), and in this case one excited C-H bond breaks while the other excited C-H bond remains in the products, resulting in an C-H stretch excited products.