Reaction of hot H atoms with CDCl3

Energetic hydrogen atoms generated by photolysis of HBr or HI react with CDCl₃ by abstracting either a deuterium atom (1) or a chlorine atom (2): The integral probability of reaction (2) has been measured for several defined initial translational energies of H^*, and the phenomenological threshold energy is 31 ± 14 kJ/mol. For initial translational energies in the range of 66–121 kJ/mol, the ratio of the integral probabilities of Cl abstraction and of D abstraction, when normalized to equal numbers of Cl and D atoms, is 2.4 ± 0.3. The interpretation of the integral reaction probabilities in terms of the excitation functions of reactions (1) and (2) is discussed. Measurements of the moderating effect of CO₂ on reactions (1) and (2) show that CDCl₃ is slightly more effective than CO₂ as a moderator of H atoms in the energy range of 90–30 kJ/mol.