Highly resolved polarized absorption spectra of single-crystal [Ru(bpy)₃](PF₆)₂

Abstract

Polarized absorption spectra of neat single-crystal [Ru(bpy)₃](PF₆)₂ at 300 and 5 K are presented. The spectra show pronounced vibronic structure and it is possible to assign the vibrations to known Raman frequencies. Furthermore, the different electronic states corresponding to the vibronic transitions are identified and assigned. The assignment of the lowest excited states - observed in absorption - agrees with an earlier classification of the emitting states. In particular, the E perpendicilar c-polarized transition A'₁ ‹—› 2E’ (classified in D'₃), at 17816 cm⁻¹, is found at the same energy (experimental error: ± 1 cm⁻¹) in emission and absorption and represents a zero-phonon, zero-vibron transition. The low-energy part of the E parallel c-polarized spectrum (below = 24000 cm⁻¹) is not dominated by a series of different electronic states but by a 1600 cm⁻¹ progression with zero-vibron transition at 18770 cm⁻¹.