PERTURBATION OF THE THERMAL EQUILIBRIUM DISTRIBUTION IN THERMAL DISSOCIATION OF DIATOMIC MOLECULES,

For a harmonic oscillator with a finite number of discrete levels the decomposition rate constant depends upon the probability of transition of the oscillator in the discrete spectrum P-n,n1 and upon the probability of transition to the continuous spectrum P-infinity. In actual cases when P-infinity is sufficiently large in comparison with P-10 the rate of decomposition is determined by the rate of delivery of low energy level molecules to the dissociation threshold. The maximum value of the preexponential factor is here of the order of the number of collisions. The distribution function for decomposing oscillators for periods greater than the time of relaxation of the vibration energy 1k-o decreases exponentially. With increase in energy it decreases more rapidly than the Boltzman function exp -EkT, tending to zero for the last discrete level, when the decomposition rate constant, depending upon P-10 and P-infinity, attains its maximum value. The fraction of molecules decomposing in the time t approx.1k-o, which were initially at a lower temperature, is less than the ratio between the time of relaxation and the characteristic time of reaction. The remaining molecules decompose according to an exponential law with the characteristic time 1k. Author