Spectroscopy of yttrium dimers in argon matrices

The absorption and resonance Raman spectra of yttrium dimers (Y-2) in argon matrices are measured for the first time. The absorption spectrum (scatter ing depletion spectrum SDS) shows a weak, broad transition centered near 48 5 nm. Resonance Raman spectra obtained by exciting into this absorption ban d with several visible laser lines (465.5-496.5 nm) give a single, sharp pr ogression with up to ten Stokes transitions. These data give omega (e)=184. 4(4) cm(-1), with omega (e)x(e)=0.30(3) cm(-1), leading to a spectroscopic dissociation energy of D-e=3.5(4) eV. Comparison of our results with severa l ab initio calculations adds confirmation to the assignment of the ground state of Y-2 to be the (1)Sigma (+)(g) state. (C) 2000 American Institute o f Physics. [S1063- 777X(00)01709-6].