Adsorption Of Rare Gases Research Articles

Theory of local-work-function determination by photoemission from rare-gas adsorbates

Photoemission from rare-gas atoms adsorbed on surfaces offers a unique analytical tool for the determination of the work function appropriate to microscopically small regions of a substrate surface. The chemical activity of small regions, such as steps and corners, and the fact that the local work function determines the relative energies of substrate and adsorbate electronic levels makes the determination of the local work function potentially very important. Here we provide a detailed microscopic picture of the special aspects of rare-gas adsorption that make such measurements possible. The discussion is based on the results of parameter-free self-consistent-field calculations for individual rare-gas atoms on a free-electron metal.

Density functional approach to physical adsorption of rare gases on metal surfaces

The potential energy curves for helium and argon adsorbed on a metal surface are obtained directly from the microscopic contributions to the interaction energy in the electron gas approximation. The method of calculation presented is simple and straightforward and yet gives sensible numerical results.

Rare gas fractionation patterns in terrestrial samples and the Earth‐atmosphere evolution model

Rare gas abundances in various terrestrial materials can be classified into three distinct fractionation patterns: type 1 shows a progressive enrichment in the heavier gases (shales, natural gases, holocrystalline submarine basalts, seawater and groundwater), type 2 shows a large enrichment of Ne and a slight apparent enrichment of Xe (glassy margins of submarine basalts, a subaerial basalt, an olivine xenolith from Hawaii), and type 3 shows large enrichments of Ne, Kr, and Xe relative to Ar (thucolite and a shale sample). The type 1 pattern is formed by the low‐temperature adsorption of rare gases usually via the rare gases dissolved in seawater. The type 2 pattern is interpreted as a combination of high‐temperature diffusion, solubility, and bulk melting in the mantle. The type 3 pattern probably represents a hybrid pattern. These patterns are consistent with an earth‐atmosphere evolution model which assumes (1) that the present rare gas abundances in the atmosphere closely approximate the rare gas inventory of the whole earth except for xenon and (2) that the average rare gas abundance pattern in the solid earth is roughly similar to that in the atmosphere except for Xe.

Calculated band structure of rare gases adsorbed on graphite

The potential field for the adsorption of rare gases on graphite has been calculated by adopting the hypothesis of additivity and a central 6–12 potential law to describe pairwise interactions. The parameters characterizing the interaction law have been chosen by keeping into account the experimental adsorption data and the structure of graphite. The motion of the adsorbed species in the potential field so defined has been studied by solving the Schrödinger equation for different values of the wave vector characterizing the translational properties of the eigenstates. A plane wave variational treatment has been adopted using symmetry adapted combinations of plane waves as basis functions and exploiting the Fourier expansion of the potential as proposed by Steele. The resulting band structure gives useful information about the degree of mobility of the adsorbed gases.

Experimental method for obtaining exact isobars of the adsorption of rare gases on single crystal surfaces: A Besnard and A Schram, Vide, 29 (169), 1974 275–282, ( in French)

Experimental method for obtaining exact isobars of the adsorption of rare gases on single crystal surfaces: A Besnard and A Schram, Vide, 29 (169), 1974 275–282, ( in French)

Anisotropy of the work function change in physical adsorption

Smoluchowski's concept of the surface double layer of bare metals is extended for physical adsorption of rare gas atoms on metal surfaces. With the use of the polarization approach it is possible to show that the work function decrease on physical adsorption of rare gases is anisotropic. A simple rule is suggested according to which the work function change produced by physical adsorption of the given rare gas on different crystal faces of the same metal [-Δφ( hkl)] decreases with increasing work function of the bare face [φ 0( hkl)] and/or with increasing packing density of the bare face. The former correlation is quantitative, whereas the latter correlation is only qualitative. The above predictions are compared with the first data available in the literature.

Calculated potential energies for the adsorption of rare gases on graphite

Calculated potential energies for the adsorption of rare gases on graphite

Les différentes étapes de la formation d'un film adsorbé de gaz rare ou de méthane sur une surface uniforme de graphite

Many examples show that the growth by adsorption of a crystal on a uniform surface takes place by successive monomolecular layers, as a consequence, the adsorption isothermes present a series of steps. The data obtained previously could be interpreted by supposing that each layer is formed either by building up of a single phase (steps of sigmoid shape) or by transition from a dilute to a condensed phase (steps with only one vertical part). The adsorption of rare gases or methane on the basal planes of graphite described in this paper, gives an example of a more complex growth of an adsorbed layer.This is the case for the first layer which passes through three successive two-dimensional states: presumably “gas”, “liquid” and “solid”; the two-dimensional solid may undergo rearrangements. The first step is then made up from several “sub-steps”.The comparison of our data with other data obtained by low energy electron diffraction shows that the first layer is different from the others not only by the diversity of the events accompanying its formation, but also by its higher density.

Rare gas adsorption on solids of the lunar regolith

This article analyzes the composition and concentration data on rare gases in the lunar solids taken in the Apollo 11 and 12 missions. The results indicate, among others, the following striking facts: 1. 1. Rare gas retention by the lunar materials is primarily by adsorption rather than absorption. 2. 2. The origin of the rare gases is primarily solar wind rather than indigenous or radiogenic. 3. 3. The accommodation coefficient of the lunar regolith for rare gases seems amazingly high. This is indicated by almost negligible fractionation; the composition of rare gases in the breccia, soil, and type A crystalline rocks is astonishingly close to that in solar wind. 4. 4. “Structural adsorption” potentials of rare gases on lunar solids appear amazingly high on the basis of the adsorption concentrations and a tenuous lunar “atmosphere.” Intense surface activation of the lunar materials is thus indicated.

Measurements on field adsorption of neon and helium and the field ionization of a helium-neon mixture

The field ionization of a helium-neon mixture is investigated. The behavior can be explained in terms of field adsorption of neon. Experimental values for the binding energy, the adsorption rate and desorption rate are obtained. At high fields, field desorption of neon is observed. The enhancement of field ionization due to the rare-gas adsorption is measured.

Rare gases on the Earth and in meteorites

Analysis of abundance patterns of rare gases Ne22, Ar36, Kr84 and Xe130 on Earth and in ordinary and carbonaceous chondrites is presented. A mechanism of chemical adsorption of rare gases at the planetesimal stage during their accretion is proposed to generate the abundance pattern of the heavy rare gases on the Earth. The calculated values for Xe and Kr agree well with the observed values whereas for Ar, the agreement is poor.

Adsorption of rare gases on poly(vinyl chloride)

Adsorption of argon and krypton on a high area poly(vinyl chloride) adsorbent in the temperature range 65–75°K was investigated. Enthalpies, entropies and free energies of adsorption were evaluated from the isotherms. The enthalpy of adsorption of argon was found to be 1.94 kcal/mole at a coverage of 0.9 monolayer, a value higher than that found on fluorocarbons or unsubstitutes hydrocarbon polymers but lower than that for poly(methylmethacrylate). Several lines of evidence indicate that the adsorbent is highly heterogeneous with respect to adsorption energies. The spreading pressures indicate that high area polymeric adsorbents may have abnormally high surface free energies.

1131. Adsorption of rare gases on evaporated alkali halide films

1131. Adsorption of rare gases on evaporated alkali halide films

The Adsorption of Gases on Ion Exchanged Mica. II. Thermodynamics of Rare Gas Adsorption

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Adsorption of Gases on Ion Exchanged Mica. II. Thermodynamics of Rare Gas AdsorptionGeorge L. Gaines Jr.Cite this: J. Phys. Chem. 1958, 62, 12, 1526–1530Publication Date (Print):December 1, 1958Publication History Published online1 May 2002Published inissue 1 December 1958https://doi.org/10.1021/j150570a014RIGHTS & PERMISSIONSArticle Views39Altmetric-Citations7LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (546 KB) Get e-Alerts

Tests of a Simplified General Model for Adsorption of Rare Gases on Solids.

Tests of a Simplified General Model for Adsorption of Rare Gases on Solids.