Dynamics of multidimensional nuclear tunneling in the chain-ethylene chlorination at liquid-helium temperature

• Published in: Chemical physics letters 1991-04, Vol.179 (4), p.334-338
• Main Authors: Benderskii, V.A., Goldanskii, V.I., Makarov, D.E., Misochko, E.Ya
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; Kinetics and mechanisms; Organic chemistry; Reactivity and mechanisms
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/0009-2614(91)85162-P

The structure of the mixed ethylene—chlorine 1:1 crystal, and the reactive center which forms in this crystal due to ethylene-chain chlorination and consists of the radical C 2H 4Cl and the molecule Cl 2, are calculated by means of intermolecular-interaction-energy minimization. The lattice deformation created in previous processes of chain growth results in a shortening of the CCl distance between C 2H 4Cl and Cl 2 to 3.4 Å. As compared to the equilibrium van der Waals distance of 3.6 Å, and reduces the barrier height for conversion in the reactive center. The tunneling is shown to take place through a vibrational-adiabatic barrier of the three-dimensional PES, taking into account two intra- and one inter-molecular vibrations. This barrier height is 1.5 kcal/mol, and the tunneling length and mass are 0.55 Å and 17 m H respectively. The rate constant at T = 0 is 10 2 s −1, in accordance with experimental data.