Determination of excited state potential functions from continuum resonance Raman scattering: Excitation of 79Br2 from the visible to the UV region

Abstract

AbstractHigh‐resolution polarized and depolarized resonance Raman spectra of isotopically pure molecular bromine (79Br2) with Δν = 1–5 were recorded using the argon laser lines at 501.7, 496.5, 488.0, 476.5, 457.9, 363.8, 351.1 and 333.6 nm and the Kr laser line 413.1 nm. Using a high‐sensitive CCD camera, the experimentally obtained spectra have better signal‐to‐noise ratios than some of the spectra already published. All observed spectra were also calculated using second‐order perturbation theory. The high sensitivity of resonance Raman band shapes to changes in the position of excited potential curves gives the possibility of determining the potential functions of the excited states 1II1u and 3II0+u in the energy range between 20 000 and 30 000 cm−1 very accurately. These potentials allow a satisfactory description of all observed spectra, including those of the overtones, in contrast to earlier work.