The chemiluminescent (CL) reactions Of group 2 metal elements (Ca, Sr, and Ba) in both the ground and metastable states with various OH- and/or O-containing molecules have been studied in a beam-gas configuration. In reactions with OH-containing molecules, it was found that while the ground state atoms produce both the metal oxide and metal hydroxide in excited electronic states, the metastable atoms produce solely metal hydroxide. Also, spectral changes have been observed which can be attributed to changes in the reaction exoergicity or the collision geometry dictated by various scattering gases. Computer simulations of the observed CL spectra have afforded further insight into the potential energy surfaces which govern the reactions.