Electrostatic trapping of ammonia molecules

Bethlem, Hendrick L.; Berden, Giel; Crompvoets, Floris M. H.; Jongma, Rienk T.; Roij, André J. A. van; Meijer, Gerard

doi:10.1038/35020030

Cited by 472 publications

(420 citation statements)

References 22 publications

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“…They are rather deep (on the order of 1 K), and by changing the electrode geometries or the applied voltages, a variety of trapping potentials can be created. 12a, 18,[30][31][32][33][34] The ability to trap molecules in their hfs states is of special importance because all molecular ground states as well as the majority of states of larger molecules are hfs. This is important for techniques that provide further cooling such as evaporative cooling, a key step in reaching quantum degeneracy.…”

Section: Introductionmentioning

confidence: 99%

A Linear AC Trap for Polar Molecules in Their Ground State

et al. 2007

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A linear AC trap for polar molecules in high-field seeking states has been devised and implemented, and its characteristics have been investigated both experimentally and theoretically. The trap is loaded with slow 15 ND 3 molecules in their ground state (para-ammonia) from a Stark decelerator. The trap's geometry offers optimal access as well as improved loading. We present measurements of the dependence of the trap's performance on the switching frequency, which exhibit a characteristic structure due to nonlinear resonance effects. The molecules are found to oscillate in the trap under the influence of the trapping forces, which were analyzed using 3D numerical simulations. On the basis of expansion measurements, molecules with a velocity and a position spread of 2.1 m/s and 0.4 mm, respectively, are still accepted by the trap. This corresponds to a temperature of 2.0 mK. From numerical simulations, we find the phase-space volume that can be confined by the trap (the acceptance) to be 50 mm 3 (m/s) 3 .

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Section: Introductionmentioning

confidence: 99%

A Linear AC Trap for Polar Molecules in Their Ground State

et al. 2007

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“…RbCs [2]. Alternatively, cold dilute gas ensembles can be created by buffer-gas loading [3] or electric-field manipulation of naturally occurring molecules like ND 3 [4,5], H 2 CO [6], metastables like CO [7] or radicals like YbF [8], OH [9], NH [10]. So far all the cold molecules made available with electric-field-based methods have a Stark effect (in their relevant states) which is predominantly linear in the important range up to 150 kV/cm.…”

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confidence: 99%

Water vapor at a translational temperature of1K

et al. 2006

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We report the creation of a confined slow beam of heavy-water (D2O) molecules with a translational temperature around 1 kelvin. This is achieved by filtering slow D2O from a thermal ensemble with inhomogeneous static electric fields exploiting the quadratic Stark shift of D2O. All previous demonstrations of electric field manipulation of cold dipolar molecules rely on a predominantly linear Stark shift. Further, on the basis of elementary molecular properties and our filtering technique we argue that our D2O beam contains molecules in only a few ro-vibrational states. Cold dilute molecular systems are rapidly emerging as a front line area at the interface of quantum optics and condensed matter physics [1]. An increasing subset of this activity centers around the creation of cold dilute gases of molecules possessing electric dipole moments. These in particular, owing to their long-range anisotropic interaction, hold the promise of novel physics, where twoand many-body quantum properties can be systematically studied. Cold dilute gases of dipolar molecules can be produced by forging a tight bond between two chemically distinct species of laser-cooled atoms, e.g. RbCs [2]. Alternatively, cold dilute gas ensembles can be created by buffer-gas loading [3] Here we report the creation of a slow beam of heavywater (D 2 O) molecules, which experience a quadratic Stark effect. The cold D 2 O molecules are filtered from a room-temperature thermal gas [6] and have a translational temperature around 1 kelvin. Because the Stark shifts are quadratic in the electric field, it follows that forces exerted by inhomogeneous electric fields are relatively small for D 2 O compared to molecules with similar dipole moments but with linear Stark shifts. It is therefore by no means obvious that significant quantities of slow D 2 O molecules can be produced by means of electric-field-based methods. Our experimental result therefore underlines the versatility of the velocityfiltering method. It is an enabling step towards future trapping of molecules for which the ratio of elastic to inelastic collisions is expected to be more favorable than for molecules with linear Stark shifts [11]. An additional advantage of the quadratically Stark-shifted molecules like D 2 O is the possibility to perform precise spectroscopic measurements insensitive to stray electric fields, to the first order. Moreover, water is abundant in interstellar space at low densities and temperatures from a few kelvin upward, playing an important role in the chemistry of molecular clouds [12]. The conditions in these clouds are remarkably close to those achieved in our experiment, opening up the possibility to investigate in the laboratory chemical reactions under conditions found in space.This Letter is structured as follows. First we discuss general features of Stark shifts of molecular states with particular references to D 2 O. We then present our experimental work with D 2 O. This is followed by arguing from first principles that the resulting beam of D 2 O is domina...

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“…Here, molecules were decelerated from 285 m/s to 53 m/s. This final velocity is very close to typical velocities that are used to load electrostatic traps [3,30,31]. A slight increase of the phase angle would have been sufficient to achieve this but the detection of the particles would have been very difficult due to dispersion of the bunches during the time-of-flight from the end of the decelerator to the interaction zone.…”

Section: Deceleration and 3d Effectsmentioning

confidence: 64%

Cold SO2 molecules by Stark deceleration

et al. 2008

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Abstract.We produce SO2 molecules with a centre of mass velocity near zero using a Stark decelerator. Since the initial kinetic energy of the supersonic SO2 molecular beam is high, and the removed kinetic energy per stage is small, 326 deceleration stages are necessary to bring SO2 to a complete standstill, significantly more than in other experiments. We show that in such a decelerator possible loss due to coupling between the motional degrees of freedom must be considered. Experimental results are compared with 3D Monte-Carlo simulations and the quantum state selectivity of the Stark decelerator is demonstrated.

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Electrostatic trapping of ammonia molecules

Cited by 472 publications

References 22 publications

A Linear AC Trap for Polar Molecules in Their Ground State

A Linear AC Trap for Polar Molecules in Their Ground State

Water vapor at a translational temperature of1K

Cold SO2 molecules by Stark deceleration

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