Electronic Structure and Spectroscopy of CuBe

Electronic spectra for CuBe were recorded using resonantly enhanced one-color, two-photon ionization techniques. Several vibronic progressions were observed, permitting characterization of the 4²Σ⁺, 5²Σ⁺, 3²Π and 4²Π excited states. Rotational resolution was achieved for a few bands, permitting determination of the ground state rotational constant. Attempts to record laser-induced fluorescence or two-color ionization spectra were unsuccessful. This was attributed to predissociation of the excited states. Density functional theory and <i>ab initio</i> electronic structure calculations were used to facilitate assignment of the observed states. Potential energy curves obtained from these calculations indicated that states arising from the Cu­(3d⁹4s²) + Be­(2s²) dissociation asymptote were well-positioned to cause predissociation of the observed states.