The electronic spectrum of cryogenic ruthenium-tris-bipyridine dications in vacuo

We report the electronic spectrum of the prototypical ruthenium coordination complex Ru(bpy)3 ²⁺ (bpy = 2, 2′-bipyridine) by messenger tagging with N2 in a cryogenic ion trap and photodissociation spectroscopy of mass selected Ru(bpy)3 ²⁺ ⋅ N2 ions. We observe individual electronic bands and groups of bands with unprecedented detail, particularly in the usually unresolved metal-to-ligand charge transfer region of thespectrum. By comparing our experimental results with time-dependent density functional theory, both with and without spin-orbit interaction [Heully et al., J. Chem. Phys. 131, 184308 (2009)], we are able to assign the spectrum of the isolated ion.

DOI:  10.1063/1.4955262

Shuang Xu^†, James E. T. Smith^‡, and J. Mathias Weber^‡

^† JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, United States
^‡ JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States