PHOTOFRAGMENTATION DYNAMICS OF MG-2(CO2)(1,2)(+)

We have investigated the photofragmentation spectroscopy of Mg 2(CO2)1+2 in a reflectron time-of-flight mass spectrometer. For the linear bimolecular complex Mg 2(CO2)+, we have observed three distinct molecular absorption bands, in the red, the green, and the near uv spectral regions. In each band both Mg+ and Mg2+ fragments are observed, although with different action spectra. In the uv band, we also observe reactive fragmentation to form the chemical product Mg2O+. As an initial step in investigating the dissociation mechanism and the dynamical effects which determine the final state branching, we have carried out preliminary calculations of the low lying Mg2(CO2)+ potential energy curves in collinear geometry. Photofragmentation of the complex Mg2(CO2)2+ occurs over a broad spectral range in the visible. We have found that the addition of the second solvent molecule dramatically enhances the solvent cage effect, as evidenced by a large increase in the Mg2+/Mg+ branching ratio throughout this spectral region. © 1995 American Institute of Physics.