Highly resolved emission and absorption spectra of [ Os(bpy),] *+ doped into single-crystal Ru(bpy),2, are reported.
,
Our investigations, at low temperatures (2 < Tg 50 K) and high magnetic fields (09 H< 6 T), lead to the following results: The three lowest excited states of [ Os( bpy) 3 ]*' in this matrix are identified from zero-phonon transitions lying at 14 169 f 2 cm-'
line I), 14230f2 cm-' (line II), and 14380?2 cm-' (line III). These transitions are found at the same energies (within the experimental error of ? 2 cm-') in absorption and emission. The extinction coefficients of II and III are r+: IO' L mol-' cm-' while the transition IO) + 1 I) (line I) is strongly forbidden. However, under high magnetic fields this absorption line grows in due to a mixing of 11) with 111). A large number of vibronic peaks is identified in the emission spectra. The corresponding vibrational modes are compared to Raman and IR data of [ Ru( bpy),] *+ and [ Os( bpy),] 2+. Several distinct modes couple more strongly to the transition from the lowest excited state 1 I), others to the transition from I II), as is shown by investigating the magnetic field dependence of the emission spectra.