Water vapor at a translational temperature of1K

Abstract

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...

A Linear AC Trap for Polar Molecules in Their Ground State

“…∆V z,dec ) (8ln2) kT/m (6) molecules homogeneously over the acceptance of our trap, which is consistent with our measurements. It is interesting to compare the linear AC trap investigated in the present work with the cylindrically symmetric trap demonstrated before 35,36 and with the three phase trap, 49 which has not been implemented yet.…”

“…4 Slow molecules can also be filtered out from an effusive beam using a bent electrostatic quadrupole guide and subsequently trapped. 5,6 Inhomogeneous electric fields can be used to decelerate and trap neutral polar molecules. 7 A successful Stark deceleration has been demonstrated for a variety of molecules such as metastable CO*, 8,9 ND 3 and NH 3 , 10 OH, 11,12a OD, 12b YbF, 13,14 CH 2 O, 15 NH, 16 SO 2 , 17 and benzonitrile (C 6 H 5 CN); in addition, ND 3 , 18 OD 12b and OH 12a have been trapped.…”

Orientation of dipole molecules and clusters upon adiabatic entry into an external field

“…The subject of orientation of dipolar molecules by static electric and magnetic fields has long occupied a prominent place in the study of molecular beams, [1][2][3] and is currently enjoying renewed attention due to the introduction of "brute force" orientation methods 4,5 for stereospecific collision experiments 6,7 and spectroscopy, 8 to the development of Stark deceleration techniques for the production and storage of slow molecules, 9 to construction of electrostatic guides for cold molecules, 10 and to electric and magnetic beam deflection experiments on polar clusters ͑see, e.g., Refs. 11-16 and references therein͒.…”

Trapping of Neutral Rubidium with a Macroscopic Three-Phase Electric Trap

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