prior distribution, \(P_{0}\)

https://doi.org/10.1351/goldbook.P04852
A @[email protected] calculated on the basis of some physical model for the reaction. The distribution usually referred to is that of the products at the instant of their formation.
Source:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 178 [Terms] [Paper]