The absorption (scattering depletion) spectrum and resonance Raman spe
ctrum for Ru-2 ill an argon matrix prepared by the mass-selected ion d
eposition technique have been obtained. The absorption spectrum in the
Visible region shows a single broad transition centered at 470 nm. Re
sonance Raman spectra, obtained by excitation into this band with dye
laser radiation, display a single sharp progression with Lines at 343.
8(26) cm(-1), 681.6(32) cm(-1), 1017.5(26)cm(-1), 1350.2(25) cm(-1),an
d 1678.9(8) cm(-1). These data give omega(e) = 347.1 +/- 0.9 cm(-1) wi
th omega(e)x(e)= 1.85 +/- 1.5 cm(-1) leading to a spectroscopic dissoc
iation energy of 2.0 +/- 0.2 eV, Sidebands in the Raman spectra are in
dicative of a weak coupling (Huang-Rhys factor, S similar to 0.1-0.7)
between the dimer and the phonons of the argon host. (C) 1997 American
Institute of Physics.