Energy and chemical change
Abstract
The information theoretic approach to branching ratios has been applied to a number of different processes. The main practical conclusion of this work is that for direct, exoergic reactions with low activation barriers, even in the absence of any other knowledge, the 'prior' branching ratio, which is very easy (slide rule) to estimate, already provides a useful guide. Exact quantal close coupling computations were carried out for atomatom collisions. Comparisons were carried out with more approximate (e.g., Landau Zener) treatments leading to practical conclusions regarding the coupling constants for such processes. The information theoretic analysis and synthesis of cross sections for rotational energy transfer in atomdiaton collision was studied in considerable detail. It was found possible to simulate an entire matrix of statetostate cross sections by two constants. One of the two is just a scale factor for the absolute magnitude of the cross sections. The relative magnitudes are governed (to the first approximation) by a single parameter. It was found possible to provide ready estimates for this parameter which measures the importance of the energy 'mismatch' in the collision. The concept of the 'prior' distribution was clarified.
 Publication:

Texas Univ., Austin Report
 Pub Date:
 December 1976
 Bibcode:
 1976uta..rept.....L
 Keywords:

 Chemical Reactions;
 Information Theory;
 Atomic Collisions;
 Chemical Bonds;
 Energy Transfer;
 Excitation;
 Atomic and Molecular Physics