Explanation of high-foreign-gas-pressure effects on resonant light scattering in I 2 vapor

We demonstrate that at all pressures, the resonant scattering emission in ${\mathrm{I}}_{2}$ vapor as excited by a 501.7-nm Ar-ion laser line is dominated by the combined effects of discrete-state resonant fluorescence and dissociative-state continuum resonant Raman scattering (RRS). The changes in the emission upon increased pressures, such as relative and absolute intensities of Stokes overtones, and the variation in depolarization ratios are demonstrated to be due to the gradual quenching of the resonance fluorescence at high pressure, while the dissociative-state RRS contribution remains unaltered.