Studies on vibrational and electronic Raman effects. Resonance Raman spectroscopy of [IrCl6]2–, [IrBr6]2– and [OsBr6]2– ions

Abstract

The resonance Raman spectra of the [IrCl₆]^2–, [IrBr₆]^2– and [OsBr₆]^2– ions have been recorded with a variety of ion- and dye-laser lines and the following progressions have been observed: v₁ν₁ to v₁= 7, [IrCl₆]^2–; 6, [IrBr₆]^2–; 7, [OsBr₆]^2–: v₁ν₁+ν₂ to v₁= 4, [IrCl₆]^2–; 2, [IrBr₆]^2–; 1 ? [OsBr₆]^2–: v₁ν₁+ν₅ to v₁= 4, [IrCl₆]^2–, 4, [IrBr₆]^2–; 5, [OsBr₆]^2–. The excitation profiles of several Raman bands of the iridium (IV) complexes have been plotted in detail, and compared with the electronic spectra of the ions in each case. The incidence of electronic Raman spectra ([IrCl₆]^2– and [OsBr₆]^2– only) and relaxed fluorescence with available excitation lines is discussed.