State-to-State Reaction Dynamics in Crossed Supersonic Jets: Threshold Evidence for Non-Adiabatic Channels in F + H2
S A. Nizkorodov, W W. Harper, David Nesbitt
The reaction of F + n-H6d2^ to form HF(υ,J) + H is studied in a crossed jet apparatus under single collision conditions, using high-resolution direct absorption spectroscopy to probe the nascent rotational HF distributions. The J-dependent reactive cross-sections into HF(Ņ=3,J) are investigated over a range of center-of-mass collision energies well below the 1.9 kcal mol-1 barrier for adiabatic chemical reactions with ground state F(2P3/2) atoms. The energy dependent reaction cross-sections decrease much more slowly with Ecom then predicted by exact quantum calculations on the adiabatic F(2P3/2) + H2 surface (K. Stark and H. Werner. J. Chem. Phys., 1996, 104, 6515) In addition, product states in the HF(Ņ=3) manifold are observed that are energetically accessible only to the excited spin-orbit state F*(P1/2) + H2(j=0,1) channel. These observations strongly sugget that non-adiabatic reactions with spin-orbit excited F*(P1/2) contribute significantly in the near threshold region, in good agreement with recent calculations by M. Alexander, H Werner and D Manolopoulos (J. Chem. Phys., 1998, 109, 5710) Finally, the feasibility of high-resolution IR laser Dopplerimetry on the nascent products is illustrated on collision free HF(Ņ,J) distributions formed from reactions of F + CH4.
crossed molecular beam, potential energy surfaces, reactive scattering
, Harper, W.
and Nesbitt, D.
State-to-State Reaction Dynamics in Crossed Supersonic Jets: Threshold Evidence for Non-Adiabatic Channels in F + H<sub>2</sub>, Faraday Discussions
(Accessed May 29, 2023)