title: Stark-selected beam of ground-state OCS molecules characterized by revivals of impulsive alignment.
abstract: We make use of an inhomogeneous electrostatic dipole field to impart a quantum-state-dependent deflection to a pulsed beam of OCS molecules, and show that those molecules residing in the absolute ground state, X(1)Σ(+), |00(0)0>, J = 0, can be separated out by selecting the most deflected part of the molecular beam. Past the deflector, we irradiate the molecular beam by a linearly polarized pulsed nonresonant laser beam that impulsively aligns the OCS molecules. Their alignment, monitored via velocity-map imaging, is measured as a function of time, and the time dependence of the alignment is used to determine the quantum state composition of the beam. We find significant enhancements of the alignment (<cos(2) θ(2D)> = 0.84) and of state purity (>92%) for a state-selected, deflected beam compared with an undeflected beam.
authors.affiliation: Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C, Denmark.
authors.forename: Jens H
authors.initials: JH
authors.lastname: Nielsen
authors.forename: Paw
authors.initials: P
authors.lastname: Simesen
authors.forename: Christer Z
authors.initials: CZ
authors.lastname: Bisgaard
authors.forename: Henrik
authors.initials: H
authors.lastname: Stapelfeldt
authors.forename: Frank
authors.initials: F
authors.lastname: Filsinger
authors.forename: Bretislav
authors.initials: B
authors.lastname: Friedrich
authors.forename: Gerard
authors.initials: G
authors.lastname: Meijer
authors.forename: Jochen
authors.initials: J
authors.lastname: Küpper