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Reactive Scattering of F + HD -> HF(upsilion},J) + D: HF(upsilion},J) Nascent Product State Distributions and Evidence for Quantum Transition State Resonances



W W. Harper, S A. Nizkorodov, David Nesbitt


Single collision reactive scattering dynamics of F + HD -> HF(Ņ,J) + D have been investigated exploiting high-resolution (δυnearly equal to}0.001 cm-1)infrared laser absorption for quantum state-resolved detection of nascent HF(Ņ,J) product states. State-resolved Doppler profiles are recorded for a series of HF rovibrational transitions and converted into state-rosolved fluxes via density-to-flux analysis, yielding cross-section data for relative formation of HF(upsilion},J) at Ecom nearly equal to} 0.6(2), 1.0(3), 1.5(3), and 1.9(4) kcal/mol. State-resolved HF (Ņ,J) products at all but the lowest collision energy exhibit Boltzmann-type populations, characteristic of direct reactive scattering dynamics. At the lowest collision energy (Ecom nearly equal to} 0.6(2) kcal/mol), however, the JF(Ņ=2,J) populations behave quite anomalously, exhibiting a nearly flat distribution out to Jnearly equal to} 11 before dropping rapidly to zero at the energetic limit. These results provide strong experimental support for quantum transition state resonance dynamics near Ecom nearly equal to) 0.6 kcal/mol corresponding classically to H atom chattering between the F and D atoms, and prove to be inremarkably quantitative agreement with theoretical wave packet predictions by Skodje et al. [J. Chem. Phys. 112, 4536 (2000)]. These fully quantum state resolved studies therefore nicely complement the recent crossed beam studies of Dong et al. [J. Chem. Phys. 113, 3633 (2000)], which confirm the presence of this resonance via angle resolved differential cross-section measurements. The quantum state distributions near threshold also indicate several rotational states in the HF (upsilion}=3) vibrational manifold energetically inaccessible to F(2P3/2) reagent, but which would be consistent with a minor (5%) non-adiabatic contribution from spin orbit excited F*(2P1/2).
Journal of Chemical Physics
No. 13


collision energies, quantum transition-state resonance effec, reactive scattering


Harper, W. , Nizkorodov, S. and Nesbitt, D. (2002), Reactive Scattering of F + HD -> HF({upsilion},J) + D: HF({upsilion},J) Nascent Product State Distributions and Evidence for Quantum Transition State Resonances, Journal of Chemical Physics (Accessed May 22, 2024)


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Created March 31, 2002, Updated October 12, 2021