Troe expression

https://doi.org/10.1351/goldbook.T06517
A semiempirical description of the rate coefficient for a specific three body reaction [e.g. T06517.png] which represents well its pressure and temperature dependence in the region of transition between second and third order kinetics.
Source:
PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2218 (https://doi.org/10.1351/pac199062112167)