Knowledge Bank

Structured absorptions have been observed in a number of experiments involving group II A atoms isolated in argon and krypton matrices at $10\circ K$. Single oven experiments yielded absorptions attributed to $Mg2,Ca2$, and $Sr2$ and two-oven experiments verified the existence of CaMg, SrMg, and SrCa. Unstructured absorptions assigned to $Ba2$ and BaMg were also observed. Argon and krypton ion laser and dye laser excitation into the absorption bands mentioned above produced structured emissions for $Mg2,Ca2,CaMg$, and unstructured emissions from $Sr2$ and SrMg. Vibrational constants from the structured absorption and emission spectra are consistent with a simple M.O. picture describing a weakly bound (van der Waals’) ground state and a chemically bound excited state.