The role of solvation processes is fundamental to the understanding of chemical reaction mechanisms of importance in areas such as organic synthesis, catalysis, atmospheric chemistry and industrial processes. This proposal presents a systematic study of a solvent perturbed bimolecular chemical reaction. The comparison of the solvated reaction dynamics with existing gas phase data will allow the determination of the role-played by the solvent on the reaction mechanism. The photo-induced oxidative-addition reactions of neutral Group 2 Metal atoms with simple hydrocarbons and halocarbons have been selected for study in the presence of the solvent in this case inert rare gas solids. Specifically, the Ca + CH3F system has been chosen for examination as recently experimental data has become available for the photo-induced reaction, free in the gas phase and deposited on large argon clusters. Therefore the applicant proposes to study the fully solvated (matrix-isolated) reaction. Generally, oxidative-addition reactions conducted under solid-state conditions result in metal atom photo-insertion. Although fragmentation does occur, as in the gas phase, cage-exit is not favoured and fragment recombination processes dominate. Therefore following an identification of the reaction products and an assessment of the solvation effects in the solid-state using steady-state FTIR spectroscopy the dynamics of the excited state reaction will be investigated. The time-resolved measurements of a metal+molecule oxidative-addition reaction will be completed for the first time, using Step-Scan FTIR spectroscopy and the facilities and resources of the Low Temperature Spectroscopy Group at NUI-Maynooth. The study of reactions under these extreme states of matter (gas phase and solid-state) affords a unique opportunity for the development of understanding of solvation processes by the application of time-resolved experimental techniques