A function relating the prior distribution P 0 of product states to an observed or calculated product distribution
P. It is defined by: \[s=- \ln (\frac{P}{P_{0}})\]
Source:
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 188 (https://doi.org/10.1351/pac199668010149)