We worked for years to implement a generalized solver so we could more easily expand the aqueous chemical mechanism for cloud chemistry in EPA’s atmospheric model. A 3 stage Rosenbrock solver that enables simultaneous solution of partitioning, oxidation, equilibrium, etc. as it happens in the atmosphere is implemented and available as open source code. Read more about the governing equations and their impact on cloud chemistry predictions here: http://www.geosci-model-dev.net/10/1587/2017/
The Carlton Group 