Spectroscopy of mass-selected rhodium dimers in argon matrices

The absorption (scattering depletion) spectrum and Raman spectra for Rh2 in an argon matrix prepared by the mass selected ion deposition technique have been obtained. The absorption spectrum in the visible region shows a single broad transition centered near 495 nm Resonance Raman spectra obtained by exciting with eight visible lines (457.9–514.5 nm) of an argon ion laser give a single, sharp progression with up to four Stokes transitions. These data give ωe=283.9 (18) cm−1 with ωexe=1.83 (33) cm−1, leading to an experimental dissociation energy of 1.4±0.3 eV. The Raman results are discussed in the context of previous theoretical predictions for the dimer.