Energy effects on reaction channels and cross-sections

Energy effects on reaction channels and cross-sections 

The cross-section of a given pair of reactants for undergoing a specific channel of chemical reaction is dependent not only on the relative kinetic energy but also on the internal states of the reactants (energy and other properties such as orbital symmetry and spin multiplicity). Thus, in order to speak of the cross-section of a channel unequivocally, it is necessary to specify both the relative kinetic energy and the internal states of the reactants. 

The kinetic energy dependence is also of theoretical interest. If the microscopic cross section a for an ion—molecule reaction has the form a E) = OqE as predicted by the orbiting theory (Section 3.2), the phenomenological cross-section Q should have the form Q = Qq E ,  

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