Sliced Fluorescence Imaging Techniques for the Study of Photo‐initiated Dynamic Processes in Bulbs

Abstract To study photo‐initiated dynamic processes in bulbs, sliced fluorescence imaging techniques have been developed to obtain quantum‐state resolved information on the speed and angular distributions of reaction products, and their angular momentum polarization characteristics. For fluorescent chemical species, an unconventional experimental arrangement can generate a two‐dimensional projection of the Newton sphere from a single photolysis center. Consequently, image blurring for photo‐initiated experiments in bulbs can be dramatically diminished. A combination of optical‐optical (or infrared‐optical) double resonance excitation scheme and the fluorescence imaging detection method warrants a novel technique to acquire three‐dimensional sliced fluorescence images of scattering products. A theoretical framework, which employs a double Legendre moment analysis on the central sliced images, has been developed to determine differential cross sections and kinetic energy release of co‐products in photo‐initiated dynamic processes. Experimental images of collisional relaxations of CN photofragments from disequilibrium to equilibrium are presented to illustrate the distinctive advantage of the present method in comparison with other imaging and spectroscopic techniques.