Helium Droplets Doped With Sulfur And C-60

Clusters of sulfur are grown by passing superfluid helium nanodroplets through a pickup cell filled with sulfur vapor. In some experiments the droplets are codoped with C-60. The doped droplets are collided with energetic electrons and the abundance distributions of positively and negatively charged cluster ions are recorded. We report, specifically, distributions of S-m(+), S-m(-), and C60Sm- containing up to 41 sulfur atoms. We also observe complexes of sulfur cluster anions with helium; distributions are presented for HenSm- with n <= 31 and m <= 3. The similarity between anionic and cationic C60Sm +/- spectra is in striking contrast to the large differences between spectra of S-m(+) and S-m(-).