Experimental and theoretical electric dipole polarizabilities of Al andAl2

The static electric dipole polarizabilities of the aluminum atom and dimer have been measured by deflecting a molecular beam in an inhomogeneous electric field. Collimated aluminum-cluster beams are produced by a pulsed laser vaporization source. Deflections are determined by means of a novel position-sensitive time-of-flight mass spectrometer. The measured polarizabilities are 6.8±0.3 and 19±2 A${\mathrm{̊}}^3$ for the atom and dimer, respectively, in good agreement with the ab initio calculations presented here. The experimental techniques described here allow precise determination of the mean deflections and velocities of the particles in the beam and are generally applicable for beams produced by laser vaporization sources.