Electronic spectroscopy of ytterbium in a neon matrix.

The low-lying electronic states of Yb isolated in a solid Ne matrix are characterized through absorption and emission spectroscopy. The absorption spectra of matrix isolated Yb while pumped into its triplet states have been recorded for the first time and the 6s6p (3)P(J) → 5d6s (3)D(1, 2) transition frequencies obtained. Under matrix conditions, the structure of these states is found to be qualitatively the same as in the free atom, but the intersystem crossing rate is observed to be several orders of magnitude greater. A proposed explanation for this is curve crossings between the bound potential energy surface correlated to the 6s6p (1)P(1) state and the potential energy surfaces correlated to the 5d6s (3)D(1, 2) states in isolation. The potentials of the Yb·Ne dimer in its lowest electronic states are computed ab initio and used in a pairwise cluster model to explicitly demonstrate these curve crossings.