Velocity-tunable slow beams of cold O₂ in a single spin-rovibronic state with full angular-momentum orientation by multistage Zeeman deceleration

摘要

Cold samples of oxygen molecules in supersonic beams have been decelerated from initial velocities of 390 and 450 m s−1 to final velocities in the range between 150 and 280 m s−1 using a 90-stage Zeeman decelerator. (2 + 1) resonance-enhanced-multiphoton-ionization (REMPI) spectra of the 3sσ _g 3Î _g (C) two-photon transition of O₂ have been recorded to characterize the state selectivity of the deceleration process. The decelerated molecular sample was found to consist exclusively of molecules in the J ′′ = 2 spin-rotational component of the X ground state of O₂. Measurements of the REMPI spectra using linearly polarized laser radiation with polarization vector parallel to the decelerator axis, and thus to the magnetic-field vector of the deceleration solenoids, further showed that only the magnetic sublevel of the N′′ = 1, J ′′ = 2 spin-rotational level is populated in the decelerated sample, which therefore is characterized by a fully oriented total-angular-momentum vector. By maintaining a weak quantization magnetic field beyond the decelerator, the polarization of the sample could be maintained over the 5 cm distance separating the last deceleration solenoid and the detection region.View full textDownload full textKeywordsmultistage Zeeman deceleration, cold molecules, angular-momentum orientation, state-selective detection of O2 Related var addthis_config = { ui_cobrand: "Taylor & Francis Online", services_compact: "citeulike,netvibes,twitter,technorati,delicious,linkedin,facebook,stumbleupon,digg,google,more", pubid: "ra-4dff56cd6bb1830b" }; Add to shortlist Link Permalink http://dx.doi.org/10.1080/00268976.2012.681312