Velocity slip measurements of bismuth clusters produced by the inert gas condensation technique

The velocities of bismuth clusters produced by the inert gas condensation technique have been measured by the time of flight spectrometer. A large velocity slip has been observed between the helium carrier gas and the clusters. The translational temperature of helium has been also measured. Although the fragmentation phenomena associated with electron impact ionization precludes a precise determination of the temperature of the clusters, this temperature can be roughly estimated and our results show that a partial mass selection of neutral clusters by a velocity selector is possible.