Light-Force Technique for Measuring Cluster Polarizabilities

We report on a light-force technique to make absolute measurements of cluster polarizabilities in the gas phase. The technique relies on several important experimental components and methods, including a front-ablation cluster source to produce cold clusters, a position-sensitive time-of-flight spectrometer, glass collimating slits, and a reliable technique for timing a particular slice of the cluster beam. The cluster beam is collimated with a pair of slits and the ideal locations of the slits to maximize the observable light force is discussed. To date, the polarizability of C₆₀ at the fundamental wavelength of a Nd:YAG laser (1.064µm) has been measured.