Articles you may be interested inExamination of the Br+HI, Cl+HI, and F+HI hydrogen abstraction reactions by photoelectron spectroscopy of BrHI−, ClHI−, and FHI− J. Chem. Phys. 92, 7205 (1990); 10.1063/1.458208 Energy dependence and isotope effect for the total reaction rate of Cl+HI and Cl+HBr Thermal reaction rate constants have been determined for the reactions Cl + HI and Cl + HBr in the temperature range 220-400°K. The rates vary slowly with temperature. For Cl + HI the effective reaction cross section reaches a maximum of 31 A2 near 300 o K. A tentative reaction model is proposed in which the attacking halogen atom is attracted to the halogen end of the hydrogen halide and then rotation of the hydrogen, with little or no activation energy. completes the reaction.3936

Thermal rate constants have been determined for the reaction C1+DI and Br+HI in the temperature range 220–400 K. For C1+DI, the effective reaction cross section reaches a maximum of 18.8 Å2 near 345 K. The isotope effect increases in favor of HI from 1.5 to 2.7 as the temperature decreases from 400 to 223 K. For Br+HI, the effective reaction cross section decreases slightly with increasing temperature. The cross section at enhanced collisional energy, with various rotational energies, is determined for the reaction C1+HI (DI). It is found that a factor of 3.9 increase in translational velocity over room temperature actually decreases the cross section for C1+HI and DI by factors of 9 and 6.6, respectively. At 11.4 kcal/mole relative translational energy, the cross section for the reaction C1+HI increases by 1.2 as the rotational temperature increases from 223 to 295 K. The results are discussed in terms of a reaction model in which the attacking halogen atom is attracted to the halogen end of the hydrogen halide and then rotation of the hydrogen completes the reaction. A semiquantitative analysis shows that tunneling makes an important contribution to the isotope effect.

No abstract