RRKM THEORY CALCULATION OF UNIMOLECULAR DECOMPOSITION OF HEXAFLUOROETHANE - THERMAL ACTIVATION

The thermal decomposition of hexafluoroethane is discussed in terms of the quantum-statistical RRKM theory of unimolecular reactions. The falloff behavior is calculated at several temperatures using the approximate rotation-vibration energy-level sums of Whitten and Rabinovitch. A very loose, Gorin-type activated complex model with five active internal rotations is found to be consistent with earlier shock-tube results. Centrifugal effects, associated with a significant extension of the critical bond length in the activated complex, are found to be important and must be taken into account. The approximate method is also applied to C2H5 and satisfactory agreement is found with previous exact computations.