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MO: Fachverband Molekülphysik
MO 2: Collisions, Energy transfer and ab initio Modelling
MO 2.6: Vortrag
Montag, 29. Februar 2016, 12:15–12:30, f142
Mechanism of Forward and Backward Scattering and Modification of the Polanyi rule for reaction A+BC→AB+C and AC+B — •Victor Wei-Keh Chao — Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan, R.O.China — Group 1101, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R.China — Victor Basic Res. Labor. e.V. 33602 Bielefeld, Germany
The Polanyi rule - The reactive cross sections can be enhanced with transl. and vibr. prepared BC on the early and late barrier PESs, respectively, has contributed immensely over 60 years. Results of H+FCl(v,j)→HF+Cl and HCl+F at Erel=0.5-20 kcal/mol show, considerations of 1. Mass combination of A, B and C, 2. Width and steepness of the entrance channel, 3. Space on the barrier top, are necessary. The entrance channel is very steep and narrow (For HCl is ca.3 times wider), and barrier top for HF (For HCl is ca.5 times wider) is very small compared with the bond length of FCl, whatever cause both transl. and vibr. enhancement on the early barrier PESs. Appearance of max. of curvature σAB-vBC can be similarly explained. The forward and backward scattering mechanism can also be clarified. The nascent, light AB (HF) and heavy C (Cl) will be forwards and backwards scattered, respectively, on the barrier top because of the exoergicity and mass ratio AB/C < 1; heavy AC (HCl) and light B (F) backwards and forwards, with AC/B >1. Support of financial aids by Section 11, DICP, CAS (KF-2013-01, KF-2014-01), and VBR are acknowledged.