In order to be climatically relevant, an atmospheric cluster initially composed of a few molecules needs to form adducts by uptaking other vapors. Each step of the particle formation process has to be efficient and offer enough stability to the cluster to ensure growth to the next size out-competes coagulation, absorption by larger particles, or evaporation. Thus, understanding the intricate details of energetics and kinetics at each step is paramount. Additionally, simulation of the aforementioned processes also requires exact rates and thermodynamic parameters such as binding free energy (∆G). Here, we describe laboratory MS experiments that have probed the kinetics and thermodynamics of cluster formation and reactions. We also highlight the need for experimental validation of predicted rates and thermochemical parameters. The kinetics of base exchange in small ammonium bisulfate, ammonium nitrate and ammonium methanesulfonate clusters were examined in a FT-ICR-MS. These studies focused on measuring the rates of the substitution of amines such as methylamine, dimethylamine and trimethylamine for ammonia and found that the observed substitutions were all pseudo first order reactions. Figure shows a typical reaction profile and statistical fit for the reaction of the [(NH 4 + ) 8 (HSO 4 -) 7 ] + cluster with dimethylamine.