Measuring the van der Waals forces between a Rydberg atom and a metallic surface

Anderson, A.; Haroche, S.; Hinds, E. A.; Jhe, Wonho; Meschede, Dieter

doi:10.1103/physreva.37.3594

Cited by 76 publications

(46 citation statements)

References 10 publications

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“…Possibly experiments have been tried that just did not work. It is known that the transmission of Rydberg atoms through metal slits with micron scale separations can be affected by atom-surface interactions [794,795]. Gratings constructed from insulating materials can be used for neutral atoms, but even small amounts of charging in the grating structure could result in large electric fields, which are not compatible with Rydberg atoms.…”

Section: Antimatter Gravity Experimentsmentioning

confidence: 99%

Experimental progress in positronium laser physics

2018

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Abstract. The field of experimental positronium physics has advanced significantly in the last few decades, with new areas of research driven by the development of techniques for trapping and manipulating positrons using Surko-type buffer gas traps. Large numbers of positrons (typically ≥10 6 ) accumulated in such a device may be ejected all at once, so as to generate an intense pulse. Standard bunching techniques can produce pulses with ns (mm) temporal (spatial) beam profiles. These pulses can be converted into a dilute Ps gas in vacuum with densities on the order of 10 7 cm −3 which can be probed by standard ns pulsed laser systems. This allows for the efficient production of excited Ps states, including long-lived Rydberg states, which in turn facilitates numerous experimental programs, such as precision optical and microwave spectroscopy of Ps, the application of Stark deceleration methods to guide, decelerate and focus Rydberg Ps beams, and studies of the interactions of such beams with other atomic and molecular species. These methods are also applicable to antihydrogen production and spectroscopic studies of energy levels and resonances in positronium ions and molecules. A summary of recent progress in this area will be given, with the objective of providing an overview of the field as it currently exists, and a brief discussion of some future directions.

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Section: Antimatter Gravity Experimentsmentioning

confidence: 99%

Experimental progress in positronium laser physics

2018

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“…Less is known about the van der Waals interactions of electronically excited metastable and Rydberg atoms, in particular the C 3 coefficient is not accurately known. Some time ago, transmission through narrow channels [4] and level shifts in closed or semi-infinite cavities [5,6] have been studied. Recently, inelastic electronic transitions on passage over a metal edge [7] and reflection from surfaces and (reflection) gratings [8] have been measured.…”

mentioning

confidence: 99%

The van der Waals potential between metastable atoms and solid surfaces: Novel diffraction experimentsvs.theory

Bruehl¹,

Fouquet²,

Grisenti³

et al. 2002

Europhys. Lett.

109

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Highly polarizable metastable He* (2 3 S) and Ne* (2 3 P) atoms have been diffracted from a 100 nm period silicon nitride transmission grating and the van der Waals coefficients C3 for the interaction of the excited atoms with the silicon nitride surface have been determined from the diffraction intensities out to the 10th order. The results agree with calculations based on the non-retarded Lifshitz formula.PACS numbers: 34.50.Dy, 03.75.BeThe van der Waals (vdW) force between atoms, molecules and solid surfaces is of far reaching importance in many branches of physics, chemistry, and biology [1]. For larger distances, retardation due to the exchange of virtual photons has to be included, while for distances much smaller than the smallest wavelength a non-retarded approach can be used. The theoretical foundations for atom-surface interactions were laid in the pioneering work of Lifshitz [2]. In this case the non-retarded vdW potential has the form −C 3 /l 3 in leading order, where l is the atom-surface separation and C 3 depends on the atom, its electronic state, and on the electronic states of the solid.For groundstate rare gas atoms the C 3 coefficients have recently been measured with good accuracy [3]. Less is known about the van der Waals interactions of electronically excited metastable and Rydberg atoms, in particular the C 3 coefficient is not accurately known. Some time ago, transmission through narrow channels [4] and level shifts in closed or semi-infinite cavities [5,6] have been studied. Recently, inelastic electronic transitions on passage over a metal edge [7] and reflection from surfaces and (reflection) gratings [8] have been measured. Currently there is great interest in these potentials, in particular for metastable helium which is widely used in atom optics [9] as well as in surface physics [10] and for which Bose-Einstein condensation has recently been achieved [11]. The atom-surface van der Waals potentials could soon become relevant in guiding slow metastable rare gas atoms along microstructures [12] or in studying collective effects of Bose-Einstein condensed metastable He* atoms in contact with a surface.From a theoretical point of view atoms in excited states are of particular interest. Their polarizability α is expected to increase as n 7 , with correspondingly much stronger interactions [13]. Therefore it is not obvious whether approximate formulae for the groundstate atom-surface vdW potential are still applicable for excited atoms. Moreover, with the much stronger vdW interaction new effects such as higher multipole coefficients [14] can be expected.In this article, an effective but simple experimental method is used to determine the atom-surface vdW coefficient C 3 for metastable rare gas atoms. It is based on diffraction of an atomic beam from a nanostructured transmission grating with a period of only 100 nm. Modifications in the hierarchy of the intensities of the higher order maxima in the diffraction pattern have been shown to be directly related to the strength C 3 of the atom...

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“…The behavior of Rydberg species at surfaces has been studied by several groups in the form of experiments with transmission through grids [11,12], ionization in surface fields [13,14] and polarization by surface fields [15]. In one case a beam experiment has been performed to study the ionization at glancing incidence on a surface [16], which is the first but hopefully not the last of more exact molecular beam experiments treating the Rydberg-surface interactions.…”

Section: Properties Of Rydberg Speciesmentioning

confidence: 99%

Scattering of a potassium atom beam from potassium promoted catalyst surfaces via electronically excited clusters

Holmlid

1995

Z Phys D - Atoms, Molecules and Clusters

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Abstract. Surface scattering of potassium atom beams is observed from surfaces of a potassium promoted catalyst, which is known to emit Rydberg K* species and clusters K*. The surfaces studied are cut flat from pellets of an industrial catalyst, the promoted iron oxide catalyst for styrene production. The scattering is studied in the temperature range 500-1000 K in an UHV apparatus with a K atom beam at 45 ° towards the normal, with surface ionization and ion detection over an angular range of -90 ° to + 90 ° with respect to the surface normal. Bilobular scattering patterns are observed, which are mainly back-scattering at low temperatures, below 750 K. A large signal due to ions emitted in the backwards direction is also found with a voltage on the sample. This back-scattering indicates that the scatterers are heavy clusters outside the surface. The ion formation in the backwards direction is proposed to be due to collisions with electronically excited clusters K* of the type recently observed by field ionization detection (Kotarba et al. 1994). The bilobular scattering transforms into asymmetric patterns with a larger forward (specular) lobe at higher temperatures, above 800 K. Only a small fraction of the beam molecules is scattered off the surface. The scattering is well described by inelastic surface scattering theory. This shows that the actual scattering surface is rather flat, which is proposed to be due to an antibondii~g Rydberg type interaction, of long range (hundreds of A), between the impinging excited K atom and the surface. The temperature dependence of the neutral scattering gives a barrier of 0.96 eV, close to what is generally found for Rydberg species emission from such surfaces. At larger K s~r-face densities, the contributions to the peaks from the beam flux is shown to agree with this picture involving collisions with excited clusters outside the surface.

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Measuring the van der Waals forces between a Rydberg atom and a metallic surface

Cited by 76 publications

References 10 publications

Experimental progress in positronium laser physics

Experimental progress in positronium laser physics

The van der Waals potential between metastable atoms and solid surfaces: Novel diffraction experimentsvs.theory

Scattering of a potassium atom beam from potassium promoted catalyst surfaces via electronically excited clusters

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