title: Selecting the size of helium nanodroplets using time-resolved probing of a pulsed helium droplet beam.
abstract: We show that helium nanodroplets generated using a pulsed valve undergo velocity dispersion according to their size. This makes it possible to use temporal selection to probe nanodroplets of a particular size within the pulsed gas profile rather than changing the expansion conditions as is done when using continuous helium nanodroplet sources. The variation in mean droplet size achievable within a single gas pulse can extend over more than an order of magnitude.
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Shengfu
authors.initials: S
authors.lastname: Yang
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Ellis