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Experiments have revealed an attractive interaction between pairs of particles that is mediated by a surrounding quantum gas. The finding paves the way for a detailed study of the properties of such mediated interactions. Fermion-mediated interactions between bosons., Author(s): Georg M. Bruun Author Affiliations: New interactions seen in an ultracold gas Many of us have sat in a boat that is being rocked by the waves from another [...]

Except forming two Cs-rich minerals like pollucite and londonite, cesium generally occurs in trace amounts in potassium-bearing minerals owing to its very low Clarke value and large ionic radius. However, in the Koktokay#3 pegmatite (Altai, NW China), lepidolite is extremely enriched in cesium (typically 21-26 wt% [Cs.sub.2]O). Cs-enriched lepidolite is restricted to the inner of the pegmatite, where four types of occurrence are characterized by using in situ techniques (EMP: electron microprobe, micro-XRD: micro-area X-ray diffractometer and Raman probe: micro-area Raman spectrometer) as: (1) outer zones on Cs-poor lepidolite cores; (2) fine overgrowths on muscovite veinlets; (3) veinlets in Cs-poor lepidolite and (4) veinlets in elbaite. There is an inverse correlation between K and Cs and in terms of [sup.VI]Al versus Cs/(K+Cs), the Cs-dominant micas are an analog of the Li-rich mica polylithionite. Micro-XRD patterns and micro-Raman spectra indicate that Cs-dominant polylithionite structurally corresponds to minerals of the lepidolite series. According to its distribution and compositional characteristics, the Cs-dominant polylithionite seems to have formed at the magmatic to hydrothermal transition stage of pegmatitic magma evolution as a result of marginal replacement of early-formed lepidolite by Cs-rich fluids. Alternatively, it may have formed through direct precipitation from Cs-rich fluids. The results of the present study have important implications for the storage of nuclear waste in that Li mica such as polylithionite is a good candidate for immobilizing high-level radioactive cesium waste.

A new model for the direct correlation function (DCF) and the experimental effective pair potentials are used to predict the low-k behavior of the structure factor S(k) of rubidium and cesium. The results indicate that the potentials are not very accurate, at least for the moderate densities, in regard to predicting S(k), although these potentials are able to generate the pressure-volume-temperature (p-v-T) behavior of alkali metals precisely.

The V(V) oxo sulfato compound CsVO2SO4 is isolated from binary molten salt system V2O5-Cs2S2O7, which is related to the industrial catalyst used for oxidation. The crystal structure and spectroscopic properties are reported for the second compound, formed in this binary system.

The environmental availability of trace radiocesium ([sup.137]Cs) was studied in soils devoid of weathered micas. The soils were developed from basaltic ash, within a sequence Udand [right arrow] Tropept [right arrow] Udalf [right arrow] Udult from Cameroon. Tropepts and Udalfs are halloysite-rich and they exhibit a large cation exchange capacity (CEC) and a strong exchange selectivity for K probably due to the presence of halloysite-smectite mixed-layered days. The [sup.137]Cs mobility was evaluated in the B horizons through (i) a physicochemical approach using the radiocesium interception potential concept (RIP) and a sequential sorption-desorption procedure, (ii) a biological test assessing the [sup.137]Cs rhizospheric mobilization ([sup.137]Cs-RM). in a constant [K.sup.+]--[Ca.sup.2+] background solution, one of the Tropepts and the Udalfs fixed about 76% of the initial [sup.137]Cs loading. The second desorption phase in acidic conditions was more discriminating: the Udalfs fixed about 40%, while the other soils fixed 5 to 20% of the initial [sup.137]Cs+ loading. The [sup.137]CsRM was generally small (3-15%) in all samples and was negatively correlated with the RIP (439-1836 [micro]mol [g.sup.-1]). The specific retention of [sup.137]Cs in these soils was thus largely similar to that obtained in soils that contain weathered micas. It demonstrates the presence of [sup.137]Cs specific sites in halloysitic soils devoid of such minerals. These sites might be associated with halloysite-smectite mixed-layered days. They were probably formed following wetting-drying cycles in soils heavily fertilized with K.

Inactivation of the L-type [Ca.sup.2+] current ([I.sub.CaL]) was studied in isolated guinea pig ventricular myocytes with different ionic solutions. Under basal conditions, [I.sub.CaL] of 82% of cells infused with [Cs.sup.+]-based intracellular solutions showed enhanced amplitude with multiphasic decay and diastolic depolarization-induced facilitation. The characteristics of [I.sub.CaL] in this population of cells were not due to contamination by other currents or an artifact. These phenomena were reduced by ryanodine, caffeine, cyclopiazonic acid, the protein kinase A inhibitor H-89, and the cAMP-dependent protein kinase inhibitor. Forskolin and isoproterenol increased [I.sub.CaL] by only ~60% in these cells. Cells infused with either N-methyl-v-glucamine or [K.sub.+]-based intracellular solutions did not show multiphasic decay or facilitation under basal conditions. Isoproterenol increased [I.sub.CaL] by ~200% in these cells. In conclusion, we show that multiphasic inactivation of [I.sub.CaL] is due to [Ca.sub.2+] -dependent inactivation that is reversible on a time scale of tens of milliseconds. [Cs.sub.+] seems to activate the cAMP-dependent protein kinase pathway when used as a substitute for [K.sub.+] in the pipette solution. L-type calcium current; calcium-dependent inactivation; facilitation; phosphorylation; cesium

We report a class of molecules with extremely low ionization enthalpies, one member of which has been determined to have a gas-phase ionization energy (onset, 3.51 electron volts) lower than that of the cesium atom (which has the lowest gas-phase ionization energy of the elements) or of any other known closed-shell molecule or neutral transient species reported. The molecules are dimetal complexes with the general formula [M.sub.2][(hpp).sub.4] (where N is Cr, Mo, or W, and hpp is the anion of 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine), structurally characterized in the solid state, spectroscopically characterized in the gas phase, and modeled with theoretical computations. The low-energy ionization of each molecule corresponds to the removal of an electron from the delta bonding orbital of the quadruple metal-metal bond, and a strong interaction of this orbital with a filled orbital on the hpp ligands largely accounts for the low ionization energies., The phenomena of oxidation (electron loss) and reduction (electron gain) are fundamental to chemistry. Even when these processes do not occur as such, more complex chemical processes and properties, such [...]

Combined surface analysis techniques of time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) were employed for studying the surface chemistry of highly oriented pyrolytic graphite (HOPG) that is bombarded with energetic cesium (Cs(super +)) ions. The experimental findings suggest that the cesium implanted in HOPG exists in an oxidized state rather than in a metallic state and Cs(super +) ion bombardment was responsible for the surface modification of HOPG, which resulted in controlled defect production and enhanced oxygen adsorption.

Synthesis of two new quaternary silver selenoarsenates Cs(sub 3)AgAs(sub 4)Se(sub 8) and CsAgAs(sub 2)Se(sub 4) is achieved through the methanolothermal reaction of Li(sub 3)-AsSe(sub 3) and AgBF(sub 4) in the presence of alkali metal sources CS(sub 2)CO(sub 3) and CsCl. Both compounds are layered materials consisting of infinite(super 1)-[AsSe(sub 2)](super -)chains that are connected by Ag(super +) ions in trigonal planar and retrahedral coordination environments for Cs(sub 3)AgAs(sub 4)Se(sub 8) and CsAgAs(sub 2)Se(sub 4), respectively.

Research designed to select a highly cesium-selective ligand in aqueous medium is presented. Attention was also given to determining the best conditions for using this ligand in a nanofiltration-complexation process to bring about Cs+/Na+ separation.

Research has been conducted on the cesium 5-cyano-1,2,3,4-tetrazolate. The preparation of cesium by 3+2 cycloaddition reaction of CsN (sub)3 and (CN ) (sub)2 in SO (sub)2 is described.

Research has been conducted on the sodium, potassium and cesium salts. Results indicate that cesium and potassium locate between salicylaldimine ligands and sodium resides within the salicylaldimine oxygen planes.

Research has been conducted on the iodopalladates with palladium in various oxidation states. The synthesis of the compounds from HI solution is discussed.

Researchers in Spain used four organic soils to analyze the drying of cesium within soils.

Research has been conducted on the molecular structures of four crown ether adducts. The use of crystallization in their preparation is described.

Supramolecular self-assembly is an integral step in the formation of many biological structures. Here we report a DNA pentaplex that derives from a metal-assisted, hydrogen bond-mediated self-assembly process. In particular, cesium ions are found to induce pentameric assembly of DNA bearing the nonstandard nucleobase iso-guanine. The pentaplex was designed by using a simple algorithm to predict nucleobase structural requirements within a quintet motif. The design principles are general and should extend to complexes beyond pentaplex. Structures exhibiting molecularities of five or more were previously accessible to peptides, but not nucleic acids.

Research has been conducted on the cesium hypochlorite or hypobromite. The formation of N,N-dichloroamino- or N,N-dibromoamino-tris(trifluoromethyl)borates has been examined.

The effect of solvent and counterion on the rate constants for bond shift (kBS) and intramolecular charge transfer (kCT) in the bicyclooctatetraenyl dianion was investigated through dynamic NMR spectroscopy. Results showed an increase in the kBS and kCT values in the order K < Na

The linear isotherm regularity (LIR), a thermodynamic equation of state, was used to predict the metal-non-metal transition that occur when density decreases. Results revealed several changes in liquid structure while the transition is occurring, indicating a deviation from the linearity predicted by the LIR. An appropriate equation of state was then derived and used to predict a transition for liquids CS, Rb, Na and Hg. The predictions were found to agree well with experimental results. The transition was also observed to be neither first order nor second order.

The transient response of an optically pumped cesium beam tube to square wave frequency and amplitude modulation was examined. The frequency transient was calculated assuming a phase difference phi of either 0 or pi between the two oscillatory fields. Theoretical and experimental data are shown to demonstrate that, contrary to the frequency transient, the amplitude transient depends on the direction of switching.

The aggregation and alkylation of the cesium enolate of 2-p-biphenylylcyclohexanone (CsBPCH) has been studied. CsBPCH is produced directly in THF by reacting ketone with a cesium base. Its UV-vis spectrum has an isobestic point at 404.0 nm and an extinction coefficient of 24 800. CsBPCH is a mixture of monomer and dimer ion pairs at concentrations from 10 raised to the negative fifth power to 10 raised to the negative third power M.

The interaction of sodium and cesium chloride salts with calcium silicate hydrates (C-S-H) was investigated using solid-state nuclear magnetic resonance spectroscopy. Results showed that Cs+ and Na+ have a liking for the C-S-H surface, but each behave differently due to their different hydration energy. Moreover, the cations may be located in a diffuse ion swarm in hydrated C-S-H, but would form outer-sphere complexes in dry C-S-H.

The compound Cs7In4Bi6 was produced by fusion of stoichiometric mixture of the pure elements. The structure was based on In-centered tetrahedra of bismuth sharing edges to form folded chains. The latter are connected through In-In bonds in a complicated three-dimensional network. The structure can be described as being carved out from the layered PbO-type structure of the parent group III-V compound of InBi. According to EHMO computations and magnetic measurements, Cs7In4Bi6 is a wide band-gap semiconductor.

The mechanisms of the cesium cation complexation by 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis (N,N-diaethylaminocarbonyl)methoxy calix(4)arene are investigated in a binary solution of deuterated acetonitrile and deuterated chloroform. (super 1)H and (super 133)Cs nuclear magnetic resonance spectroscopy are utilized in the experiment. It is shown that the first complexed Cs(super +) is located in the cavity comprising four phenolic and four carbonyl oxygens, while the second Cs(super +) is loosely bound by the amido complexes. The decomplexation exhibits a unimolecular dissociation mechanism.

Research was conducted to synthesize and characterize the novel polyoxometalate (H2PW9Ni4O34(OH)3(H2O)6)2- using IR spectroscopy, elemental analysis, magnetic measurements and polarography. The magnetic properties of the Cs2(H2PW9Ni4O34(OH)3(H2O)6)*5h2O were dominated by well-isolated Ni4O4 fragments in a polyoxometalate matrix which permits the direct measurement of the exchange interaction of the paramagnetic cluster without interference from intercluster interaction.

A study was conducted to analyze the application of coherent population trapping for the realization of a cesium coherent microwave emitter without population inversion. A novel approach was developed to promote the implementation of a microwave frequency standard where the linear light shift is absent and the thermal noise limit for the frequency instability is below 10(super -12). It was based on the coherence characteristics of laser radiation.

The behavior of Cs+ cations dissolved in an anisotropic synthetic polymer structure was studied to determine the interactions between the Cs+ ions and the polymeric chains. Results show strong interactions between Cs+ ions and the polymeric chains. Cations undergo an anisotropic motion similar to those of polymeric segments in both swelled and dried structures. The anisotropic character of the Cs+ orientation in dried materials also increased with increasing temperature.

A study was conducted to analyze ab initio computations utilizing density functional theory within the local density approximation on PbO during the alpha-phase and idealized CsCl structure. An interactive matrix diagonalization technique was utilized to solve Kohn-Sham equations. Results indicated that the stabilization of the alpha-PbO structure over the CsCl structure correlated with the mixing of lead 6p states into the filled antibonding O 2p and Pb 6s states.

A study was conducted to analyze the interaction of copper, palladium and cesium atoms on regular and defect sites on the SiO2 surface using cluster models. Hartree-Fock, density functional theory and multireference configuration interaction techniques were utilized to determine the bonding of the metal atoms at several sites. Results indicated that the two-coordinated bridging oxygens of the triple bond surface of Si-O-Si are unreactive.

Research was conducted to examine the diffusional mobility of water, Cs and Li counterions in oriented DNA fibers using NMR self-diffusion calculations as a function of varying water content and salt concentration. A detailed study of the hydration structure and the counterion coordination was carried out based on the molecular dynamics simulation trajectories. Simulation and experimental results are in agreement that Li ion diffusion is considerably slower than the Cs ion diffusion.

Ultraviolet spectral analysis of the cesium enolate of p-phenylisobutyrophenone in tetrahydrofuran (THF) reveals that the spectrum varies with the concentration of the solution. Singular value determinations over a wide range of concentration show that more dilute solutions have longer wavelength maxima. Further investigations also reveal that ion pair monomers are the dominant species in alkylation reactions of cesium enolates in THF.

Research was conducted to examine the effect of Cs+ on the function of the cardiac sarcoplasmic reticulum (SR) in skinned cardiac myocytes. Saponin was used to permeabilize isolated rat ventricular myocytes which were subsequently perfused with a solution containing 150 nmol/1 Ca2+ and 10 mu-mol/1 fura 2. Results indicate that Cs+ slows the flux of Ca2+ across the SR membrane which might be explained by the blocking of the SR K+ channel.