title: Photoassociative spectroscopy at long range in ultracold strontium.
abstract: We report photoassociative spectroscopy of 88Sr(2) in a magneto-optical trap operating on the 1S0-->3P1 intercombination line at 689 nm. Photoassociative transitions are driven with a laser red detuned by 600-2400 MHz from the 1S0-->1P1 atomic resonance at 461 nm. Photoassociation takes place at extremely large internuclear separation, and the photoassociative spectrum is strongly affected by relativistic retardation. A fit of the transition frequencies determines the 1P1 atomic lifetime (tau=5.22+/-0.03 ns) and resolves a discrepancy between experiment and recent theoretical calculations.
authors.affiliation: Department of Physics and Astronomy and Rice Quantum Institute, Rice University, Houston, TX 77251, USA.
authors.forename: S B
authors.initials: SB
authors.lastname: Nagel
authors.forename: P G
authors.initials: PG
authors.lastname: Mickelson
authors.forename: A D
authors.initials: AD
authors.lastname: Saenz
authors.forename: Y N
authors.initials: YN
authors.lastname: Martinez
authors.forename: Y C
authors.initials: YC
authors.lastname: Chen
authors.forename: T C
authors.initials: TC
authors.lastname: Killian
authors.forename: P
authors.initials: P
authors.lastname: Pellegrini
authors.forename: R
authors.initials: R
authors.lastname: Côté