title: Control and imaging of O(1D2) precession.
abstract: Larmor precession of a quantum mechanical angular momentum vector about an applied magnetic field forms the basis for a range of magnetic resonance techniques, including nuclear magnetic resonance spectroscopy and magnetic resonance imaging. We have used a polarized laser pump-probe scheme with velocity-map imaging detection to visualize, for the first time, the precessional motion of a quantum mechanical angular momentum vector. Photodissociation of O(2) at 157 nm provides a clean source of fast-moving O((1)D(2)) atoms, with their electronic angular momentum vector strongly aligned perpendicular to the recoil direction. In the presence of an external magnetic field, the distribution of atomic angular momenta precesses about the field direction, and polarization-sensitive images of the atomic scattering distribution recorded as a function of field strength yield 'time-lapse-photography' style movies of the precessional motion. We present movies recorded in various experimental geometries, and discuss potential consequences and applications in atmospheric chemistry and reaction dynamics.
authors.affiliation: Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
authors.forename: Shiou-Min
authors.initials: SM
authors.lastname: Wu
authors.forename: Dragana Č
authors.initials: DČ
authors.lastname: Radenovic
authors.forename: Wim J
authors.initials: WJ
authors.lastname: van der Zande
authors.forename: Gerrit C
authors.initials: GC
authors.lastname: Groenenboom
authors.forename: David H
authors.initials: DH
authors.lastname: Parker
authors.forename: Claire
authors.initials: C
authors.lastname: Vallance
authors.forename: Richard N
authors.initials: RN
authors.lastname: Zare
mesh_terms: D001272:Atmosphere / Q000737:chemistry; D055598:Chemical Phenomena; D017666:Deuterium Oxide / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D056004:Molecular Dynamics Simulation; D010100:Oxygen / Q000737:chemistry*; D010782:Photolysis
chemical_list: D017666:Deuterium Oxide; D010100:Oxygen