- constantCrossSection
Constant Cross-Section
To model a cross-section that does not depend on any other
variables, use this kind.
constantCrossSection Attributes
- crossSection (float, required)
- A constant, in square meters, for the cross section. 
Example constantCrossSection Block
<RxnRate rxnRate>
  kind = constantCrossSection
  crossSection = 1.25e-20
</RxnRate>