Polarized and depolarized continuum resonance Raman scattering of molecular iodine: accurate determination of repulsive states

We have recorded high-resolution polarized and depolarized resonance Raman spectra of molecular iodine with excitation by argon-ion laser lines at 496.5, 488.0, and 476.5 nm up to the seventh, and with 457.9 nm up to the fifth, overtone. These spectra were also calculated numerically applying second-order perturbation theory. In contrast to earlier publications on this subject, special emphasis was put on obtaining highly reliable polarized and depolarized spectra. The variations of the spectral band shapes and depolarization ratios obtained at different excitation wavelengths could be explained by means of the specific contributions of the two excited electronic states [Formula: see text] and 1П1u. About 60 different experimentally obtained spectra were finally used to derive the positions of the two excited-state potentials involved in this type of light scattering. The derivation was done by comparison of the experimental and theoretically simulated spectra where parameters of the 1П1u as well as of the [Formula: see text] state potentials were varied. Key words: resonance Raman scattering, diatomic molecules, potentials, excited electronic states.