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

Published

April 1, 2002

Author(s)

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

Abstract

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 E_com 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 (E_com 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 E_com 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(²P_3/2) reagent, but which would be consistent with a minor (5%) non-adiabatic contribution from spin orbit excited F*(²P_1/2).

Citation

Journal of Chemical Physics

Volume

116

Issue

No. 13

Pub Type

Journals

Keywords

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

Citation

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 July 18, 2024)