Bioresource and Agricultural Engineering Commons^™

Linearized Theory Of Peridynamic States, S. A. Silling

United States Department of Energy: Publications

A state-based peridynamic material model describes internal forces acting on a point in terms of the collective deformation of all the material within a neighborhood of the point. In this paper, the response of a state-based peridynamic material is investigated for a small deformation superposed on a large deformation. The appropriate notion of a small deformation restricts the relative displacement between points, but it does not involve the deformation gradient (which would be undefined on a crack). The material properties that govern the linearized material response are expressed in terms of a new quantity called the modulus state. This determines …

Nebraska Statewide Wind Integration Study: Executive Summary April 2008 – January 2010, Enernex Corporation Knoxville, Tennessee, Ventyx Atlanta, Georgia, Nebraska Power Association Lincoln, Nebraska

United States Department of Energy: Publications

Wind generation is a source of electric energy that, in sufficient quantity, can cause concern for the operation of the bulk power system because of the variability and uncertainty of the wind. Most short-term planning and operational functions supporting the electric power grid are centered on supply resources that have capacity attributes – i.e. they can be dispatched (controlled up and down) to a specified power level for a specified period of time. The need to maintain very high levels of system reliability reinforces the preference in operations toward resources having capacity attributes. Wind generation usually has relatively low capacity …

Microbial And Mineralogical Characterizations Of Soils Collected From The Deep Biosphere Of The Former Homestake Gold Mine, South Dakota, Gurdeep Rastogi, Shariff Osman, Ravi K. Kukkadapu, Mark Engelhard, Parag A. Vaishampayan, Gary L. Andersen, Rajesh K. Sani

United States Department of Energy: Publications

A microbial census on deep biosphere (1.34 km depth) microbial communities was performed in two soil samples collected from the Ross and number 6Winze sites of the former Homestake gold mine, Lead, South Dakota using high-density 16S microarrays (PhyloChip). Soil mineralogical characterization was carried out using X-ray diffraction, X-ray photoelectron, and Mössbauer spectroscopic techniques which demonstrated silicates and iron minerals (phyllosilicates and clays) in both samples. Microarray data revealed extensive bacterial diversity in soils and detected the largest number of taxa in Proteobacteria phylum followed by Firmicutes and Actinobacteria. The archael communities in the deep gold mine environments were …

Microbial Reduction Of Uranium Under Iron- And Sulfate-Reducing Conditions: Effect Of Amended Goethite On Microbial Community Composition And Dynamics, H.S. Moon, L. Mcguinness, Ravi K. Kukkadapu, A.D. Peacock, John Komlos, L.J. Kerkhof, P.E. Long, Peter R. Jaffe

United States Department of Energy: Publications

There is a growing need for a better understanding of the biogeochemical dynamics involved in microbial U(VI) reduction due to an increasing interest in using biostimulation via electron donor addition as a means to remediate uranium contaminated sites. U (VI) reduction has been observed to be maximized during iron-reducing conditions and to decrease upon commencement of sulfate-reducing conditions. There are many unknowns regarding the impact of iron/sulfate biogeochemistry on U(VI) reduction. This includes Fe(III) availability as well as the microbial community changes, including the activity of iron-reducers during the uranium biostimulation period even after sulfate reduction becomes dominant. Column experiments …

Confinement Resonances In Photoionization Of Xe@C+60, A. L. D. Kilcoyne, A. Aguilar, A. Muller, S. Schippers, C. Cisneros, G. Alna’Washi, N. B. Aryal, K. K. Baral, D. A. Esteves, C. M. Thomas, R. A. Phaneuf

United States Department of Energy: Publications

Experimental evidence is presented for confinement resonances associated with photoabsorption by a Xe atom in a C₆₀ cage. The giant 4d resonance in photoionization of Xe is predicted to be redistributed into four components due to multipath interference of photoelectron waves reflected by the cage. The measurements were made in the photon energy range 60–150 eV by merging a beam of synchrotron radiation with a mass/charge selected Xe@C⁺₆₀ ion beam. The phenomenon was observed in the Xe@C³⁺₅₈ product ion channel.

Valence-Shell Photoionization Of The Chlorinelike Ca3+ Ion, Ghassan A. Alna’Washi, M. Lu, M. Habibi, R. A. Phaneuf, A. L. D. Kilcoyne, A. S. Schlachter, C. Cisneros, B. M. Mclaughlin

United States Department of Energy: Publications

Absolute photoionization measurements were performed for a mixture of ²P^o_3/2 ground-state and ²P^o_1/2 metastable-state Ca³⁺ ions over the photon energy range 65.7–104.6 eV by merging an ion beam with a beam of monochromatized synchrotron radiation. The ionization threshold energy of the ²P^o_3/2 ground state was measured to be 67.063 ± 0.015 eV, which is 0.207 eV lower than the value tabulated in the NIST database. Most of the observed resonances associated with multiple Rydberg series of autoionizing states have been assigned spectroscopically using the quantum defect form of the Rydberg …

Validation Of A Model For Static And Dynamic Recrystallization In Metals, Arthur Brown, Douglas Bammann

United States Department of Energy: Publications

In this paper, modifications are proposed to a phenomenological plasticity model to account for the evolution of recrystallization and the resultant softening behavior. The novel model includes internal state variables representing dislocation density and the spacing between geometrically necessary subgrain boundaries. In order to capture both single and multiple peak recrystallization, the model tracks the evolution of recrystallized volume fractions for multiple cycles of recrystallization, and has a set of state variables for each volume fraction. A rule of mixtures is used to determine the average stress. The model is capable of capturing static recrystallization as well as both single …

Fractionation Of Oxygen Isotopes In Phosphate During Its Interactions With Iron Oxides, Deb P. Jaisi, Ruth E. Blake, Ravi K. Kukkadapu

United States Department of Energy: Publications

Iron (III) oxides are ubiquitous in near-surface soils and sediments and interact strongly with dissolved phosphates via sorption, co-precipitation, mineral transformation and redox-cycling reactions. Iron oxide phases are thus, an important reservoir for dissolved phosphate, and phosphate bound to iron oxides may reflect dissolved phosphate sources as well as carry a history of the biogeochemical cycling of phosphorus (P). It has recently been demonstrated that dissolved inorganic phosphate (DIP) in rivers, lakes, estuaries and the open ocean can be used to distinguish different P sources and biological reaction pathways in the ratio of ¹⁸O/¹⁶O (δ¹⁸O …

Role Of Outer-Membrane Cytochromes Mtrc And Omca In The Biomineralization Of Ferrihydrite By Shewanella Oneidensis Mr-1, C. L. Reardon, Alice Dohnalkova, P. Nachimuthu, David Kennedy, D. A. Saffarini, B. W. Arey, L. Shi, Zheming Wang, D. Moore, J. S. Mclean, D. Moyles, M. J. Marshall, John M. Zachara, James K. Fredrickson, A. S. Beliaev

United States Department of Energy: Publications

In an effort to improve the understanding of electron transfer mechanisms at the microbe–mineral interface, Shewanella oneidensis MR-1 mutants with in-frame deletions of outer-membrane cytochromes (OMCs), MtrC and OmcA, were characterized for the ability to reduce ferrihydrite (FH) using a suite of microscopic, spectroscopic, and biochemical techniques. Analysis of purified recombinant proteins demonstrated that both cytochromes undergo rapid electron exchange with FH in vitro with MtrC displaying faster transfer rates than OmcA. Immunomicroscopy with cytochrome-specific antibodies revealed that MtrC co-localizes with iron solids on the cell surface while OmcA exhibits a more diffuse distribution over the cell surface. After 3-day …

Next Generation Biofuels And Advanced Engines For Tomorrow’S Transportation Needs, Sandia National Laboratories, Doe Combustion Research Facility, Doe Joint Bioenergy Institute

United States Department of Energy: Publications

In November 2009, Sandia National Laboratories hosted the Next Generation Biofuels and Advanced Engines for Tomorrow’s Transportation Needs Workshop. The event focused on the combined opportunities in biofuels and engines in the transportation sector. The workshop brought together the DOE Combustion Research Facility and the DOE Joint BioEnergy Institute along with oil companies, biofuel developers, engine manufacturers, suppliers, and experts from the university, regulatory, finance, and national laboratory communities. The intersection of biofuels and engines, if properly scaled, can meet a triad of national goals:

• Reduced climate impact

• Economic development

• Energy security through energy diversity

The workshop …

Perspectives On Energy Policy: Security, Economics, And The Environment, Sandia National Laboratories

United States Department of Energy: Publications

On March 18 and 19, 2009, Sandia National Labo­ratories and the University of California San Diego (UCSD) Sustainability Solutions Institute (SSI) brought together 27 leaders from academia, govern­ment, and the private sector to discuss key energy policy issues and proposed values- and outcomes-based approaches to energy policy. The goal of the workshop was to bring together leaders from diverse backgrounds to identify promising areas for energy policy, based on the understanding of intersecting issues, assumptions, and priorities from the national security, economic, and environmental perspectives.

Participants:  Charles Kennel, University of California, San Diego; Les Shephard, Sandia National Laboratories; Michael Aimone, …

90-Billion Gallon Biofuel Deployment Study -- Executive Summary, Sandia National Laboratories

United States Department of Energy: Publications

This study concludes that 90 billion gallons per year of biomass-derived ethanol can be produced and distributed with enduring government commitment and continued technological progress. Specifically, the model projects that 90 billion gallons of ethanol can be produced per year in the U.S.: 15 billion gallons per year from corn ethanol, with the balance from cellulosic ethanol.

Recovery Of Biodiesel Precursors From Heterotrophic Microalga Chlorella Protothecoides, Peter B. Merkle

United States Department of Energy: Publications

This working paper describes an experimental program to assess the suitability of largescale separation processing of algal biomass in aqueous culture. It assumes the possibility of successful large-scale growth of heterotrophic Chlorella protothecoides to produce algal lipid/free fatty acid (FFA) biodiesel precursors.

Surface-Initiated Titanium-Mediated Coordination Polymerization From Catalyst-Functionalized Single And Multiwalled Carbon Nanotubes, Dimitrios Priftis, Nikolaos Petzetakis, Georgios Sakellariou, Marinos Pitsikalis, Durairaj Baskaran, Jimmy W. Mays, Nikos Hadjichristidis

United States Department of Energy: Publications

Single (SWNTs) and multiwalled (MWNTs) carbon nanotubes were functionalized with a titanium alkoxide catalyst through a Diels-Alder cycloaddition reaction. The catalyst-functionalized carbon nanotubes (CNTs) were used for the surface initiated titanium-mediated coordination polymerizations of L-lactide (L-LA), ε-caprolactone (ε-CL) and n-hexyl isocyanate (HIC) employing the “grafting from” technique. ¹H NMR, IR and Raman spectra showed that the precursor catalyst was successfully synthesized and covalently attached on the CNTs surface. Thermogravimetric analysis (TGA) revealed that the grafted poly(L-lactide) (PLLA) content could be controlled with time. The final polymer-grafted CNTs were readily dissolved in organic solvents as compared to the insoluble pristine …

Morphology And Deformation Mechanisms And Tensile Properties Of Tetrafunctional Multigraft Copolymers, Yongxin Duan, Mahendra Thunga, Ralf Schlegel, Konrad Schneider, Erik Rettler, Roland Weidisch, Heinz W. Siesler, Manfred Stamm, Jimmy W. Mays, Nikos Hadjichristidis

United States Department of Energy: Publications

Morphology and deformation mechanisms and tensile properties of tetrafunctional multigraft (MG) polystrene-g-polyisoprene (PS-g-PI) copolymers were investigated dependent on PS volume fraction and number of branch points. The combination of various methods such as TEM, real time synchrotron SAXS, rheo-optical FTIR, and tensile tests provides comprehensive information at different dimension levels.TEMand SAXS studies revealed that the number of branch points has no obvious influence on the microphase-separated morphology of tetrafunction MG copolymers with 16 wt % PS. But for tetrafunctional MG copolymers with 25 wt % PS, the size and integrity of PS microdomains decrease with increasing number of branch point. …

High-Pressure Micellar Solutions Of Polystyrene-Block-Polybutadiene And Polystyrene-Block-Polyisoprene In Propane Exhibit Cloud-Pressure Reduction And Distinct Micellization End Points, Winoto Winoto, Sugata P. Tan, Youqing Shen, Maciej Radosz, Kunlun Hong, Jimmy W. Mays

United States Department of Energy: Publications

Micellar solutions of polystyrene-block-polybutadiene and polystyrene-block-polyisoprene in propane are found to exhibit significantly lower cloud pressures than the corresponding hypothetical nonmicellar solutions. Such a cloud-pressure reduction indicates the extent to which micelle formation enhances the apparent diblock solubility in near-critical and hence compressible propane. Concentration-dependent pressure-temperature points beyond which no micelles can be formed, referred to as the micellization end points, are found to depend on the block type, size, and ratio. The cloud-pressure reduction and the micellization end point measured for styrene-diene diblocks in propane should be characteristic of all amphiphilic diblock copolymer solutions that form micelles in compressible …

Feasibility, Economics, And Environmental Impact Of Producing 90 Billion Gallons Of Ethanol Per Year By 2030, Todd West, Katherine Dunphy-Guzman, Amy Sun, Len Malczunski, David Reichmuth, Richard Larson, James Ellison, Robert Taylor, Vincent Tidwell, Lennie Klebanoff, Patricia Hough, Andrew Lutz, Christopher Shaddix, Norman Brinkman, Candace Wheeler, David O'Toole

United States Department of Energy: Publications

This paper addresses a national interest in investigating the potential of displacing a large fraction of U.S. gasoline use by 2030 with ethanol. This study assesses the feasibility, implications, limitations, and enablers of producing 90 billion gallons ethanol per year by 2030. We developed a dynamic supply chain model, the Biofuels Deployment Model (BDM), and conducted sensitivity analyses to determine the parameters that most affect the feasibility, cost-competitiveness, and greenhouse gas impact of large-scale ethanol production. Though we found no theoretical barriers to achieving the stated goal, we identified a number of practical obstacles that need to be addressed. In …

Biomineralization Associated With Microbial Reduction Of Fe3+ And Oxidation Of Fe2+ In Solid Minerals, Gengxin Zhang, Hailiang Dong, Hongchen Jiang, Ravi K. Kukkadapu, Jinwook Kim, Dennis Eberl, Zhiqin Xu

United States Department of Energy: Publications

Iron-reducing and oxidizing microorganisms gain energy through reduction or oxidation of iron, and by doing so play an important role in the geochemical cycling of iron. This study was undertaken to investigate mineral transformations associated with microbial reduction of Fe³⁺ and oxidation of Fe²⁺ in solid minerals. A fluid sample from the 2450 m depth of the Chinese Continental Scientific Drilling project was collected, and Fe³⁺-reducing and Fe²⁺-oxidizing microorganisms were enriched. The enrichment cultures displayed reduction of Fe³⁺ in nontronite and ferric citrate, and oxidation of Fe²⁺ in vivianite, siderite, and monosulfide …

Uranium Extraction From Laboratory-Synthesized, Uranium-Doped Hydrous Ferric Oxides, Steven Smith, Matthew Douglas, Dean A. Moore, Ravi K. Kukkadapu, Bruce Arey

United States Department of Energy: Publications

The extractability of uranium (U) from synthetic uranium-hydrous ferric oxide (HFO) coprecipitates has been shown to decrease as a function of mineral ripening, consistent with the hypothesis that the ripening process will decrease uranium lability. To evaluate this process, three HFO suspensions were coprecipitated with uranyl (UO₂²⁺) and maintained at pH 7.0 ± 0.1. Uranyl was added to the HFO post-precipitation in a fourth suspension. Two suspensions also contained either coprecipitated silicate(Si-U-HFO) or phosphate (P-U-HFO).After precipitation of the HFOs, at time intervals of 1 week, 1 month, 6 months, 1 year, and 2 years, aliquots of each …

Reduction And Long-Term Immobilization Of Technetium By Fe(Ii) Associated With Clay Mineral Nontronite, Deb Jaisi, Hailiang Dong, Andrew Plymale, James K. Fredrickson, John M. Zachara, Steve Heald, Chongxuan Liu

United States Department of Energy: Publications

⁹⁹Tc is formed mostly during nuclear reactions and is released into the environment during weapons testing and inadvertent waste disposal. The long half-life, high environmental mobility (as Tc(VII)O₄⁻) and its possible uptake into the food chain cause ⁹⁹Tc to be a significant environmental contaminant. In this study, we evaluated the role of Fe(II) in biologically reduced clay mineral, nontronite (NAu-2), in reducing Tc(VII) O₄⁻ to poorly soluble Tc(IV) species as a function of pH and Fe(II) concentration. The rate of Tc(VII) reduction by Fe(II) in NAu-2 was higher at neutral pH (pH 7.0) …

Electron Donor-Dependent Radionuclide Reduction And Nanoparticle Formation By Anaeromyxobacter Dehalogenans Strain 2cp-C, Matthew J. Marshall, Alice C. Dohnalkova, David Kennedy, Andrew Plymale, Sara Thomas, Frank Löffler, Robert Sanford, John M. Zachara, James K. Fredrickson, Alexander Beliaev

United States Department of Energy: Publications

Anaeromyxobacter dehalogenans strain 2CP-C reduces U(VI) and Tc(VII) to U(IV)O_2(s) (uraninite) and Tc(IV)O2(S) respectively. Kinetic studies with resting cells revealed that U(VI) or Tc(VII) reduction rates using H₂ as electron donor exceeded those observed in acetate-amended incubations. The reduction of U(VI) by A. dehalogenans 2CP-C resulted in extracellular accumulation of ~5 nm uraninite nanoparticles in association with a lectin-binding extracellular polymeric substance (EPS). The electron donor did not affect UO_2(S) nanoparticle size or association with EPS, but the utilization of acetate as the source of reducing equivalents resulted in distinct UO_2(S) nanoparticle aggregates that were ~50 …

The Roles Of Outer Membrane Cytochromes Of Shewanella And Geobacter In Extracellular Electron Transfer, Liang Shi, David J. Richardson, Zheming Wang, Sebastien Kerisit, Kevin Rosso, John M. Zachara, James K. Fredrickson

United States Department of Energy: Publications

As key components of the electron transfer (ET) pathways used for dissimilatory reduction of solid iron [Fe(III)] (hydr)oxides, outer membrane multihaem c-type cytochromes MtrC and OmcA of Shewanella oneidensis MR-1 and OmcE and OmcS of Geobacter sulfurreducens mediate ET reactions extracellularly. Both MtrC and OmcA are at least partially exposed to the extracellular side of the outer membrane and their translocation across the outer membrane is mediated by bacterial type II secretion system. Purified MtrC and OmcA can bind Fe(III) oxides, such as haematite (α-Fe₂O₃), and directly transfer electrons to the haematite surface. Bindings of …

Kinetics Of Uranium(Vi) Desorption From Contaminated Sediments: Effect Of Geochemical Conditions And Model Evaluation, Chongxuan Liu, Zhenqing Shi, John M. Zachara

United States Department of Energy: Publications

Stirred-flow cell experiments were performed to investigate the kinetics of uranyl [U(VI)] desorption from a contaminated sediment collected from the Hanford 300 Area at the U.S. Department of Energy Hanford Site, Washington. Three influent solutions of variable pH, Ca and carbonate concentrations that affected U(VI) aqueous and surface speciation were used under dynamic flow conditions to evaluate the effect of geochemical conditions on the rate of U(VI) desorption. The measured rate of U(VI) desorption varied with solution chemical composition that evolved as a result of thermodynamic and kinetic interactions between the solutions and sediment. The solution chemical composition that led …

Uranium Speciation As A Function Of Depth In Contaminated Hanford Sediments - A Micro-Xrf, Micro-Xrd, And Micro- And Bulk-Xafs Study, David Singer, John M. Zachara, Gordon Brown

United States Department of Energy: Publications

The distribution and speciation of U and Cu in contaminated vadose zone and aquifer sediments from the U.S. DOE Hanford site (300 Area) were determined using a combination of synchrotron-based micro-X-ray fluorescence (μXRF) imaging, micro-X-ray absorption near edge structure (μXANES) spectroscopy, and micro-X-ray diffraction (μXRD) techniques combined with bulk U L_III-edge X-ray absorption fine structure (XAFS) spectroscopy. Samples were collected from within the inactive North Process Pond (NPP2) at 8 ft (2.4 m, NPP2-8) depth and 12 ft (3.7 m, NPP2-12) depth in the vadose zone, and fines were isolated from turbid groundwater just below the water Table …

Newly Recognized Hosts For Uranium In The Hanford Site Vadose Zone, Joanne E. Stubbs, Linda A. Veblen, David C. Elbert, John M. Zachara, James A. Davis, David R. Veblen

United States Department of Energy: Publications

Uranium contaminated sediments from the U.S. Department of Energy’s Hanford Site have been investigated using electron microscopy. Six classes of solid hosts for uranium were identified. Preliminary sediment characterization was carried out using optical petrography, and electron microprobe analysis (EMPA) was used to locate materials that host uranium. All of the hosts are fine-grained and intergrown with other materials at spatial scales smaller than the analytical volume of the electron microprobe. A focused ion beam (FIB) was used to prepare electron-transparent specimens of each host for the transmission electron microscope (TEM). The hosts were identified as: (1) metatorbernite [Cu(UO_{2 …}

Oxidative Dissolution Potential Of Biogenic And Abiogenic Tco2 In Subsurface Sediments, James K. Fredrickson, John M. Zachara, Andrew Plymale, Steve M. Heald, James Mckinley, David Kennedy, Chongxuan Liu, Ponnusamy Nachimuthu

United States Department of Energy: Publications

Technetium-99 (Tc) is an important fission product contaminant associated with sites of nuclear fuels reprocessing and geologic nuclear waste disposal. Tc is highly mobile in its most oxidized state [Tc(VII)O₄⁻] and less mobile in the reduced form [Tc(IV)O₂•nH₂O]. Here we investigate the potential for oxidation of Tc(IV) that was heterogeneously reduced by reaction with biogenic Fe(II) in two sediments differing in mineralogy and aggregation state; unconsolidated Pliocene-age fluvial sediment from the upper Ringold (RG) Formation at the Hanford Site and a clay-rich saprolite from the Field Research Center (FRC) background site …

Characterization Of An Electron Conduit Between Bacteria And The Extracellular Environment, Robert Hartshorne, Catherine Reardon, Daniel Ross, Jochen Nuester, Thomas Clarke, Andrew Gates, Paul Mills, James K. Fredrickson, John M. Zachara, Liang Shi, Alexander Beliaev, Matthew Marshall, Ming Tien, Susan Brantley, Julea N. Butt, David J. Richardson

United States Department of Energy: Publications

A number of species of Gram-negative bacteria can use insoluble minerals of Fe(III) and Mn(IV) as extracellular respiratory electron acceptors. In some species of Shewanella, deca-heme electron transfer proteins lie at the extracellular face of the outer membrane (OM), where they can interact with insoluble substrates. To reduce extracellular substrates, these redox proteins must be charged by the inner membrane/periplasmic electron transfer system. Here, we present a spectro-potentiometric characterization of a trans-OM icosa-heme complex, MtrCAB, and demonstrate its capacity to move electrons across a lipid bilayer after incorporation into proteoliposomes. We also show that a stable MtrAB …

Photoionization Cross Sections For Ions Of The Cerium Isonuclear Sequence, M. Habibi, D. A. Esteves, R. A. Phaneuf, A. L. D. Kilcoyne, A. Aguilar, C. Cisneros

United States Department of Energy: Publications

Photoionization cross sections for Ce^q+ (1 ≤ q ≤ 9) ions were measured in the 105–180 eV energy range of the 4d inner-shell giant resonance by merging a mass-to-charge-ratio-selected ion beam with a beam of monochromatized synchrotron radiation. The Cowan atomic structure code was used as an aid to interpret the experimental data. Four Rydberg series for 4d→nf (n ≥ 4) and 4d→np (n ≥ 6) autoionizing excitations were assigned using the quantum-defect theory in the Ce³⁺ photoionization cross section. The experimental data show the collapse of the nf wave functions (n ≥ 4) with …

Electronic Inhomogeneity And Ag:Sb Imbalance Of Ag1−Ypb18sb1+Zte20 High-Performance Thermoelectrics Elucidated By 125te And 207pb Nmr, E. M. Levin, B. A. Cook, K. Ahn, M. G. Kanatzidis, Ames Laboratory Doe

United States Department of Energy: Publications

Using magic-angle spinning ¹²⁵Te and ²⁰⁷Pb NMR, we have discovered the presence of two phases of approximately tenfold different free-electron concentration, n, in high-performance thermoelectrics Ag_1−yPb₁₈Sb_1+zTe₂₀ (“LAST-18”), proven by pairs of Knight-shifted NMR peaks and biexponential spin-lattice relaxation. The ratio of the phases is typically 2:1 with n ≈ 2 × 10¹⁹ cm⁻³ and 0.2 × 10¹⁹ cm⁻³, respectively, determined from the spin-lattice relaxation times. ¹²⁵Te NMR spectra show that both phases contain similar concentrations of Sb. The low-n component is assigned to …

Fullerene-Encapsulated Atoms In The Light Of Synchrotron Radiation, A. M. Müller, S. Schippers, D. Esteves, M. Habibi, R. A. Phaneuf, A. L. D. Kilcoyne, A. Aguilar, L. Dunsch

United States Department of Energy: Publications

Mass-selected beams of endohedral fullerene Ce@C⁺₈₂ ions, of atomic Ce^q+ ions (q=2,3,4), and of empty fullerene-cage C⁺₈₂ ions were employed to study photoionization of fullerene-encapsulated and free cerium atoms. The Ce 4d inner-shell contributions to single and double ionization of the endohedral Ce@C⁺₈₂ fullerene have been extracted from the data and compared with expectations based on theory and the experiments with atomic Ce ions. Dramatic reduction and redistribution of the ionization contributions to Ce 4d photoabsorption is observed. More than half of the Ce 4d oscillator strength is apparently diverted to …