RAMAN EXCITATION PROFILES FOR TITANIUM TETRAIODIDE - A CONSISTENT ANALYSIS BASED ON THE TRANSFORM METHOD

The transform method is employed to reproduce the Raman excitation pro files of the nu1, 2nu1, and 3nu1 Raman bands, as well as those of the anti-Stokes components -nu1, and -2nu1 of titanium tetraiodide in cycl ohexane solution. The theoretical fit of the profiles was achieved wit h a unique set of physical parameters; in particular, the line-shape f itting was based exclusively on the linear non-Condon to linear vibron ic coupling ratio, m/xi, that optimizes at 0.055 +/- 0.005. The use of a different vibrational frequency in the excited electronic state doe s not improve the fit at any extent. From the fit of the relative inte nsities of the profiles, an absolute value of xi = 3.7 +/- 0.1 was obt ained, leading to a Ti-I bond-length variation in the excited electron ic state of 0.105 angstrom. The expressions of the transform method co rresponding to an anti-Stokes component and Stokes overtones beyond th e first are here presented explicitly with the simultaneous inclusion of linear vibronic and non-Condon couplings.