Very low work function surfaces from condensed excited states: Rydberg matter of cesium

Svensson, Robert; Holmlid, Leif

doi:10.1016/0039-6028(92)91335-9

Cited by 46 publications

(19 citation statements)

References 11 publications

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“…It was originally described as a condensate of excited atoms called CES (for condensed excited states). However, the format of their prediction was much broader than believed at that time, and the observation of RM from Cs in thermal plasmas [16] and on surfaces [6,17] demonstrated the usefulness of this concept clearly. However, since excited states are not really required but Rydberg orbits are, the generic name RM seemed more appropriate (Rydberg orbit means hydrogen-like, so all levels in a hydrogen atom are Rydberg levels with degenerate levels since no inner electrons exist).…”

Section: Introductionmentioning

confidence: 87%

“…Macroscopic parameters like the surface work function [6] and the plasma drop were studied, even with direct probing inside the alkali (Cs) plasma [21]. The highly intriguing dark passage of extremely large electron current densities over very large electrode gaps [22], and the even more intriguing extremely strong thermal electron emission from the cold electrode [16] were well described by the RM theory due to Manykin et al [13][14][15].…”

Section: Introductionmentioning

confidence: 98%

“…Methods to form RM at larger densities have been discussed in relation to cold Rydberg gases [5]. Many of these methods give large amounts and large densities of RM, suitable for use in plasma studies and studies of the condensed RM phase as a material [6,7]. However, to understand the inner structure of such a material other methods are needed to create and study the clusters which aggregate to form RM.…”

Section: Introductionmentioning

confidence: 98%

“…The first experimental studies of RM were aimed at understanding surface layers of RM [6,20] and the interface between such surface layers and thermal alkali metal plasmas [16]. Macroscopic parameters like the surface work function [6] and the plasma drop were studied, even with direct probing inside the alkali (Cs) plasma [21].…”

Section: Introductionmentioning

confidence: 99%

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Experimental Studies and Observations of Clusters of Rydberg Matter and Its Extreme Forms

Holmlid

2011

J Clust Sci

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A review is given of experimental studies of clusters of Rydberg matter (RM) with applications. This is a metallic type of matter with angular momentum l C 1 for the conduction band electrons. The atoms in RM can be one-electron atoms like K, H and D which are most used in the laboratory, or two-electron atoms like He. Mixed clusters of one-electron atoms are easily studied. This material is stable in a vacuum both in the laboratory and in interstellar space. The large stability is valid for the lowest excitation level for each atom type, at l = 1 for H(1) which is the lowest energy state for protium. Typical clusters of RM are planar with magic numbers 7, 19, 37, 61 and 91. Small planar cluster can form stacks of clusters. Close-packed clusters exist for H(1) with magic numbers 4, 6, and 12, and chain clusters mainly formed by D-D ''beads'' are common for D(1). Several methods to study RM clusters are reviewed. Stimulated spectroscopy methods like stimulated emission and stimulated Raman are emphasized. Cluster properties like large polarizability and giant magnetic dipoles are described. Results on rotational levels, vibrational levels and electronic levels are reviewed. The observational evidence for RM clusters in space is discussed in relation to the fundamental experimental studies of the specific cluster properties.

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Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Experimental Studies and Observations of Clusters of Rydberg Matter and Its Extreme Forms

Holmlid

2011

J Clust Sci

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“…8, such effects are possible due to the very long-range potential interaction between Rydberg species. This could mean the formation of a more or less well-ordered layer of Rydberg matter [43,44], i.e. a condensed phase of Rydberg states, on the sample surface with the beam closed.…”

Section: Interaction Between Beam and Surface Fluxmentioning

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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Hydrocarbon clusters from a foil diffusion source

Åman

Holmlid

1992

J Clust Sci

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Very low work function surfaces from condensed excited states: Rydberg matter of cesium

Cited by 46 publications

References 11 publications

Experimental Studies and Observations of Clusters of Rydberg Matter and Its Extreme Forms

Experimental Studies and Observations of Clusters of Rydberg Matter and Its Extreme Forms

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

Hydrocarbon clusters from a foil diffusion source

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