The absorption and resonance Raman spectra of yttrium dimers (Y2) in argon matrices are measured for the first time. The absorption spectrum (scattering depletion spectrum SDS) shows a weak, broad transition centered near 485 nm. Resonance Raman spectra obtained by exciting into this absorption band with several visible laser lines (465.5–496.5 nm) give a single, sharp progression with up to ten Stokes transitions. These data give ωe=184.4(4) cm−1, with ωexe=0.30(3) cm−1, leading to a spectroscopic dissociation energy of De=3.5(4) eV. Comparison of our results with several ab initio calculations adds confirmation to the assignment of the ground state of Y2 to be the Σg+1 state.

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