The analysis of unresolved Raman excitation profiles. 1—Totally symmetric vibrations with applications to ruthenium red and zirconium trisulfide

The problems involved in the analysis of unresolved Raman excitation profiles are studied theoretically. The aim of such an analysis is to identify vibrational parameters of the resonant state and possibly other states involved in the scattering. For totally symmetric modes, discussed in this paper, the most important of these parameters are the displacements of the equilibrium positions, the problem being to separate these parameters from vibronic line broadening. It is shown how this can be done for systems of several modes and several interfering electronically excited states by model calculations based on a multimode approach. The effect of coupling with solvent modes on vibronic lineshapes is considered explicitly. Some reported analyses based on the independent‐oscillator approach are criticized for their lack of internal consistency or their use of unacceptable parameter values. It is demonstrated that these analyses can be improved by taking multimode effects into account. For cases where the full N‐mode problem is too difficult to handle directly, a method based on interrelated n