Measurement of pick-up cross-sections of 4He clusters: Polar versus non-polar molecules

Pick-up cross-sections of free large 4 He clusters formed in free jet expansions have been measured to determine the influence of the molecular properties of target molecules in the capture process. The pick-up cross-section depends strongly on the dipole moment of the molecule. For non-polar molecules, earlier measurements of pick-up cross-sections ranging from 2000 to 4300 Å2 were ponfirmed; for polar systems, however, cross-sections between 6400 and 8100 Å2 were observed. In both cases a linear cross-section versus mass dependence is observed.