Lifetime of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>A</mml:mi><mml:mrow><mml:mo>(</mml:mo><mml:msup><mml:mi>v</mml:mi><mml:mo>′</mml:mo></mml:msup><mml:mo>=</mml:mo><mml:mn>0</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math>state and Franck-Condon factor of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>A</mml:mi><mml:mtext>−</mml:mtext><mml:mi>X</mml:mi><mml:mrow><mml:mo>(</mml:mo><mml:mn>0</mm

Wall, T. E.; Kanem, J. F.; Hudson, J. J.; Sauer, B. E.; Cho, D.; Boshier, M. G.; Hinds, E. A.; Tarbutt, M. R.

doi:10.1103/physreva.78.062509

Cited by 53 publications

(62 citation statements)

References 17 publications

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“…However, we know that when the molecule is excited strongly on the F = 1 component of the Q 11 (1/2) line, the mean number of photons scattered is 1.9 ± 0.1 [44]. This information, together with the table of branching ratios given in [43] provides an estimated value of Z = 0.91 ± 0.05. A high value for Z is to be expected since YbF closely resembles the alkaline-earth monofluorides which all have this property [45].…”

Section: Molecule Density and Saturation Of The Absorptionmentioning

confidence: 93%

“…For our experiment, it is the product of the Franck-Condon factor, Z, for the 0−0 vibrational transition, and an angular factor that accounts for the probability of returning to the same rotational and hyperfine state. The calculation of this angular factor is similar to the one presented in the appendix of reference [43].…”

Section: Molecule Density and Saturation Of The Absorptionmentioning

confidence: 94%

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Diffusion, thermalization, and optical pumping of YbF molecules in a cold buffer-gas cell

et al. 2011

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We produce YbF molecules with a density of 10 18 m −3 using laser ablation inside a cryogenicallycooled cell filled with a helium buffer gas. Using absorption imaging and absorption spectroscopy we study the formation, diffusion, thermalization and optical pumping of the molecules. The absorption images show an initial rapid expansion of molecules away from the ablation target followed by a much slower diffusion to the cell walls. We study how the time constant for diffusion depends on the helium density and temperature, and obtain values for the YbF-He diffusion cross-section at two different temperatures. We measure the translational and rotational temperatures of the molecules as a function of time since formation, obtain the characteristic time constant for the molecules to thermalize with the cell walls, and elucidate the process responsible for limiting this thermalization rate. Finally, we make a detailed study of how the absorption of the probe laser saturates as its intensity increases, showing that the saturation intensity is proportional to the helium density. We use this to estimate collision rates and the density of molecules in the cell.

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Section: Molecule Density and Saturation Of The Absorptionmentioning

confidence: 93%

Section: Molecule Density and Saturation Of The Absorptionmentioning

confidence: 94%

Diffusion, thermalization, and optical pumping of YbF molecules in a cold buffer-gas cell

et al. 2011

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“…We have not reported the deceleration of CaF previously, but the decelerator we use has the same structure as in [6] and the methods we use to produce and detect CaF are described in [18]. Both molecular species are produced by laser ablation of a target into a supersonically expanding gas jet.…”

Section: A Setupmentioning

confidence: 99%

Nonadiabatic transitions in a Stark decelerator

et al. 2010

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In a Stark decelerator, polar molecules are slowed down and focussed by an inhomogeneous electric field which switches between two configurations. For the decelerator to work, it is essential that the molecules follow the changing electric field adiabatically. When the decelerator switches from one configuration to the other, the electric field changes in magnitude and direction, and this can cause molecules to change state. In places where the field is weak, the rotation of the electric field vector during the switch may be too rapid for the molecules to maintain their orientation relative to the field. Molecules that are at these places when the field switches may be lost from the decelerator as they are transferred into states that are not focussed. We calculate the probability of nonadiabatic transitions as a function of position in the periodic decelerator structure and find that for the decelerated group of molecules the loss is typically small, while for the un-decelerated group of molecules the loss can be very high. This loss can be eliminated using a bias field to ensure that the electric field magnitude is always large enough. We demonstrate our findings by comparing the results of experiments and simulations for the Stark deceleration of LiH and CaF molecules. We present a simple method for calculating the transition probabilities which can easily be applied to other molecules of interest.

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“…[29] with the exception that ∆Λ = 0 rather than ±1, and then introduce the J-mixing discussed above to obtain the relative dipole transition matrix elements between the eigenfunctions (Table I).…”

Section: Calcium Monofluoride a Structure And Parametersmentioning

confidence: 99%

Simulations of the bichromatic force in multilevel systems

2016

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Coherent optical bichromatic forces have been shown to be effective tools for rapidly slowing and cooling simple atomic systems. While previous estimates suggest that these forces may also be effective for rapidly decelerating molecules or complex atoms, a quantitative treatment for multilevel systems has been lacking. We describe detailed numerical modeling of bichromatic forces by direct numerical solution for the time-dependent density matrix in the rotating-wave approximation. We describe both the general phenomenology of an arbitrary few-level system and the specific requirements for slowing and cooling on a many-level transition in calcium monofluoride (CaF), one of the molecules of greatest current experimental interest. We show that it should be possible to decelerate a cryogenic buffer-gas-cooled beam of CaF nearly to rest without a repumping laser and within a longitudinal distance of about 1 cm. We also compare a full 16-level simulation for the CaF B ↔ X system with a simplified numerical model and with a semiquantitative estimate based on 2-level systems. The simplified model performs nearly as well as the complete version, whereas the 2-level model is useful for making order-of-magnitude estimates, but nothing more.

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Lifetime of theA(v′=0)state and Franck-Condon factor of theA−X(0

Cited by 53 publications

References 17 publications

Diffusion, thermalization, and optical pumping of YbF molecules in a cold buffer-gas cell

Diffusion, thermalization, and optical pumping of YbF molecules in a cold buffer-gas cell

Nonadiabatic transitions in a Stark decelerator

Simulations of the bichromatic force in multilevel systems

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