In the last years, the increasing synergism among the major pillars of atmospheric chemistry, namely observational measurements, laboratory investigation and atmospheric modeling, is providing invaluable insights into the intricate phenomena occurring in the atmosphere. In this framework, computational chemistry can be of considerable help for gaining additional information about ground and excited state properties of chemical species, their photochemical pathways, chemical reaction mechanisms, and rate coefficients. In particular, kinetic and mechanistic features of reactions are usually interpreted employing the Arrhenius equation to describe the variation of the rate constant with temperature 4