title: Evidence for an energy level substructure of molecular states in helium droplets.
abstract: The pure tunneling inversion transition of ammonia embedded in (4)He droplets was investigated in the microwave frequency range. We observed a spectrum that consists of a sharp peak, only 15 MHz wide, on top of a broad feature. The peculiar line shape could be simulated with an empirical model and is a clear experimental evidence for an energy level substructure of molecular states in doped helium droplets.
authors.affiliation: Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Lehnig
authors.forename: Nicholas V
authors.initials: NV
authors.lastname: Blinov
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Jäger