reaction probability, Pr

https://doi.org/10.1351/goldbook.R05176
The probability that a reaction occurs when two particles undergo a collision. If Nc is the number of collisions occurring in unit time, and Nr the number of reactions occurring in unit time: Pr=NrNc.
Source:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 184 [Terms] [Paper]