Measurement of Lithium Cluster Polarizabilities

A light-force technique for measuring polarizabilities is being used to measure the polarizability of low-mass lithium clusters (Li_N, N<=20). The technique uses a pulsed Nd:YAG laser to produce an intense, standing-wave field that changes the downstream spatial distribution of a beam of clusters. The clusters are ionized downstream and sent through a time-of-flight spectrometer. This latter process maps the changed downstream spatial distribution of the clusters into a changed pattern in time. The different cluster masses are recorded using a multichannel plate and a fast digital scope. Their temporal shapes are then fitted to extract the polarizabilities. footnote[1]This work is supported by the National Science Foundation under contract CHE-9420441 and by the Department of Energy under contract LLNL/DOE B278815.