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Taylor, Paul C.J.; Roberts, M. W.; Gateva, S.; Clarke, R.B.M.; Barwood, G. P.; Rowley, W. R. C.; Gill, P.

doi:10.1103/physreva.56.2699

Cited by 65 publications

(54 citation statements)

References 19 publications

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“…We use standard techniques to cool and detect single ions or small ion crystals on the cycling transition 2 S 1/2 -2 P 1/2 near 369 nm wavelength (see Fig. 1 25 . The ion is spatially overlapped with the centre of the ultracold neutral atom cloud by displacing the two independent trapping potentials.…”

Section: Methodsmentioning

confidence: 99%

Controlling chemical reactions of a single particle

et al. 2012

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. For these studies, single particles provide a clean and well-controlled experimental system. Here, we report on the experimental tuning of the exchange reaction rates of a single trapped ion with ultracold neutral atoms by exerting control over both their quantum states. We observe the influence of the hyperfine interaction on chemical reaction rates and branching ratios, and monitor the kinematics of the reaction products. These investigations advance chemistry with single trapped particles towards achieving quantum-limited control of chemical reactions and indicate limits for buffer-gas cooling of single-ion clocks.The full control over all quantum mechanical degrees of freedom of a chemical reaction allows the identification of fundamental interaction processes and the steering of chemical reactions. This task is often complicated in heteronuclear systems by a multitude of possible reaction channels, which make theoretical treatments very challenging. Therefore, focussing on the best-controlled experimental conditions, such as using state-selected single particles and low temperatures, is crucial for the investigation of chemical processes at the most elementary level. The hybrid system of trapped atoms and ions offers key advantages in this undertaking. On the one hand, ion traps offer a large potential well depth to trap the reaction products for precision manipulation and investigation. On the other hand, contrary to pure ionic systems, there is no Coulomb barrier between the particles to fundamentally prevent chemical reactions at low temperatures. Therefore, the efforts to control the motional degrees of freedom of one 4-6 and both 7-13 reactants in hybrid atom-ion systems have paved new ways towards cold chemistry. The yet missing component is the simultaneous control of the internal degrees of freedom.The interaction between an ion and a neutral atom at long distances is dominated by the attractive polarization interaction potential V (r), which is of the formHere, C 4 = α 0 q 2 /(4π 0 ) 2 is proportional to the neutral particle polarizability α 0 , q is the charge of the ion, 0 is the vacuum permittivity, and r is the internuclear separation. Inelastic collisions take place at short internuclear distances. In the cold, semiclassical regime this requires collision energies above the centrifugal barrier [14][15][16] . Such processes are referred to as Langevin-type collisions and happen, even for cold collisions 7,9 , at an energyindependent rate γ Langevin = 2π √ C 4 /µ n a . Here µ is the reduced mass of the collision partners and n a is the neutral atom density.Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK. *e-mail: cs540@cam.ac.uk. More subtle effects, such as the hyperfine interaction, which may lead to atom-ion Feshbach resonances, are not included in the polarization potential and have been investigated only theoretically so far 17 . Experimentally, reactive Langevin collisions in the polarization potential have been investigated in ground state collisi...

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Section: Methodsmentioning

confidence: 99%

Controlling chemical reactions of a single particle

et al. 2012

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“…The clock laser excites ions into the long-lived 2 F 7/2 state, which is repumped to the ground state via the highly excited 1 D[5/2] 5/2 state. Taylor et al [9,10] investigated transitions from the 2 F 7/2 state, including the 864.8 nm 2 F 7/2 -3 D[5/2] 3/2 and 3.43 µm 2 F 7/2 -2 D 5/2 transitions, finding the 638.6 nm 2 F 7/2 -1 D[5/2] 5/2 transition to be the most suitable for repumping.…”

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confidence: 98%

Optogalvanic spectroscopy of metastable states in Yb+

et al. 2011

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The metastable 2 F 7/2 and 2 D 3/2 states of Yb + are of interest for applications in metrology and quantum information and also act as dark states in laser cooling. These metastable states are commonly repumped to the ground state via the 638.6 nm 2 F 7/2 -1 D[5/2] 5/2 and 935.2 nm 2 D 3/2 -3 D[3/2] 1/2 transitions. We have performed optogalvanic spectroscopy of these transitions in Yb + ions generated in a discharge. We measure the pressure broadening coefficient for the 638.6 nm transition to be 70 ± 10 MHz mbar −1 . We place an upper bound of 375 MHz/nucleon on the 638.6 nm isotope splitting and show that our observations are consistent with theory for the hyperfine splitting. Our measurements of the 935.2 nm transition extend those made by Sugiyama et al., showing wellresolved isotope and hyperfine splitting (Sugiyama and Yoda in IEEE Trans. Instrum. Meas. 44: 140, 1995). We obtain high signal-to-noise, sufficient for laser stabilisation applications (Streed et al. in Appl. Phys. Lett. 93: 071103, 2008).

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“…Here we present a measurement of the branching fractions for decay from the metastable 5D 5/2 level in Ba + . To our knowledge, a branching fraction measurement on such a long-lived atomic level as barium's 5D 5/2 level (τ ∼ 30 s) has not previously been done, although the branching fraction of the metastable 2 D 5/2 level in Yb + (τ ∼ 7 ms) has been measured [10]. The long lifetime of the metastable state in barium introduces additional systematic effects that must be carefully considered and controlled.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the branching fractions and lifetime of the5D5/2level ofBa+

et al. 2014

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We present a measurement of the branching fractions for decay from the long-lived 5D 5/2 level in 138 Ba + . The branching fraction for decay into the 6S 1/2 ground state was found to be 0.846(25)stat (4)sys. We also report an improved measurement of the 5D 5/2 lifetime, τ5D 5/2 = 31.2(0.9) s. Together these measurements provide the first experimental determination of transition rates for decay out of the 5D 5/2 level. The low (< 7 × 10 −12 Torr) pressure in the ion trap in which these measurements were made simplified data acquisition and analysis. Comparison of the experimental results with theoretical predictions of the transition rates shows good agreement.

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Investigation of the2S1/2−2D

Cited by 65 publications

References 19 publications

Controlling chemical reactions of a single particle

Controlling chemical reactions of a single particle

Optogalvanic spectroscopy of metastable states in Yb+

Measurement of the branching fractions and lifetime of the5D5/2level ofBa+

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