Spectroscopy of yttrium dimers in argon matrices

Abstract

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 ¹Σg⁺ state.