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in creator/contributor: "Beitz, J. V."

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Speciation of Radionuclides in Natural Groundwaters, Annual Report: October 1986 through September 1987

Two ultrasensitive laser techniques, laser photoacoustic spectroscopy (LPAS) and laser-induced fluorescence (LIF), are being developed for the detection and speciation of trace levels of actinides in solutions typical of those expected in a high-level waste repository. An LPAS system was set up for these studies. Experiments were carried out to determine the detection limits of plutonium and americium in solution. Concurrently with the LPAS work, LIF studies were carried out on uranyl ion and c… more

Date: February 1988

Creator: Doxtader, M. M.; Beitz, J. V.; Reed, Donald Timothy & Bates, John K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Detection and speciation of transuranium elements in synthetic groundwater via pulsed-laser excitation

High sensitivity methods for detection and speciation of complexed transuranium ions in synthetic basalt groundwater, and simplified analogs, are being developed which exploit advances in pulsed laser technology. The first demonstration of high sensitivity detection of a transuranium ion at temperatures significantly above ambient is reported using laser photoacoustic spectroscopy (LPAS). The existence of enhanced LPAS signal amplitudes with increasing temperature in aqueous solution is confirm… more

Date: January 1, 1987

Creator: Beitz, J. V.; Bowers, D. L.; Doxtader, M. M.; Maroni, V. A. & Reed, D. T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Europium(III) interaction with a water-soluble extractant: From speciation to photodestruction

The first spectroscopic study of metal ion-THFTCA (tetrahydrofuran-1, 2,3,4-tetracarboxylic acid) coordination is reported. Luminescence studies provide evidence for predominance of a complex containing 1 Eu(+3) ion and 2 THFTCA molecules in aqueous processing nuclear waste. Evidence that THFTCA coordinates, at least in part, via carboxylate groups was found in the Eu(3+) {sup 5}D{sub 1} state fluorescence decay rates. Direct photochemical destruction of THFTCA was demonstrated in the study of … more

Date: August 1, 1994

Creator: Beitz, J. V.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Nuclear energy research initiative project final report. Report Period: October 1, 1999 - March 31, 2003

This project developed a single material approach to reducing nuclear waste volume based on a chemically functionalized porous silica that is termed Diphosil. Diphosil was created by Chiarizia and coworkers as an ion exchange medium that selectively and nearly irreversibly sorbs highly charged metal ions, such as actinides, from appreciably acidic aqueous solutions and a version of it is now commercially available. The chelating power of Diphosil is due to diphosphonic acid groups that are anch… more

Date: May 27, 2003

Creator: Beitz, J. V.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Linear and nonlinear spectroscopy of tetravalent actinide ions in CeF{sub 4}

This paper reports laser spectroscopy studies on the tetravalent actinide ions Bk{sup 4+} and Cf{sup 4+} doped into CeF{sub 4}. Fluorescence line narrowing (FLN) and spectral hole burning (SHB) were applied to unravel the complex 5f-state spectra that arise from inhomogeneous line broadening and the presence of two intrinsic metal ion sites. When a persistent spectral hole was burned in an inhomogeneously broadened zero phonon line of 1 metal atom % Cf{sup 4+} in CeF{sub 4}, satellite spectral … more

Date: October 1, 1993

Creator: Liu, G. K.; Jursich, G.; Huang, J.; Beitz, J. V. & Williams, C. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Variable temperature optoacoustic studies of 4f-states of neodymium in oxide phases

An apparatus for recording high sensitivity photoacoustic spectra from strongly light scattering samples has been constructed and tested at temperatures from 4 to 295K. The apparatus is suitable for use with air- or moisture-sensitive samples or radioactive samples requiring containment. Unlike an earlier ambient temperature photoacoustic study on Nd{sub 2}O{sub 3}, the photoacoustic bands observed from high purity Nd{sub 2}O{sub 3} in the present work agree well with the Stark components of 4f… more

Date: September 1, 1993

Creator: Beitz, J. V.; Hinaus, B. M. & Huang, Jin

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

f-state luminescence of lanthanide and actinide ions in solution

Detailed studies of the luminescence of aquated Am{sup 3+} are presented in the context of prior lanthanide and actinide ion work. The luminescing state of aquated Am{sup 3+} is confirmed to be {sup 5}D{sub l} based on observed emission and excitation spectra. The luminescence lifetime of Am{sup 3+} in H{sub 2}O solution is (22 {plus_minus} 3) ns and (155 {plus_minus} 4) ns in D{sub 2}O solution at 295 K. Judd-Ofelt transition intensity theory qualitatively describes the observed Am{sup 3+} rel… more

Date: September 1, 1993

Creator: Beitz, J. V.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Spectroscopic properties of the f-elements in compounds and solutions. [79 references]

In this systematic examination of some of the spectroscopic properties of the f-elements we deal with both the trivalent lanthanides and actinides. We summarize the present status of our energy level calculations in single crystal matrices and in aqueous solution, and compare the predicted crystal-field structure in certain low-symmetry sites with that observed. Some interesting new structural insights are thereby gained. The state eigenvectors from these calculations are then used in part in r… more

Date: January 1, 1982

Creator: Carnall, W. T.; Beitz, J. V.; Crosswhite, H.; Rajnak, K. & Mann, J. B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Vibronic interaction and crystal structure distortion in Cm sup 4+ :CeF sub 4

We have applied selective excitation to unravel the complex 5f state spectra of Cm{sup 4+} in CeF{sub 4} which arises from multiple metal ion sites and vibronic interactions. An unusual laser-induced site distortion on one of the two ion-sites has been studied. Distinct spectral lines of the distorted ion site were detected. The site distortion was found to be stable below 45 K and reverted, via a thermally activated process, at higher temperatures. Below 45 K, persistent spectral holes were bu… more

Date: January 1, 1990

Creator: Liu, G. K.; Beitz, J. V. & Carnall, W. T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Aqueous complexation of trivalent lanthanide and actinide cations by N,N,N'{sub 2},N'-tetrakis(2-pyridylmethyl)ethylenediamine.

The aqueous complexation reactions of trivalent lanthanide and actinide cations with the hexadentate ligand N,N,N{prime},N{prime}-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), have been characterized using potentiometric and spectroscopic techniques in 0.1 M NaClO{sub 4} At 25 C, the stability constant of Am(TPEN){sup 3+} is two orders of magnitude larger than that of Sm(TPEN){sup 3+}, reflecting the stronger interactions of the trivalent actinide cations with softer ligands as compared to l… more

Date: June 16, 1999

Creator: Beitz, J. V.; Ensor, D. D.; Jensen, M. P. & Morss, L. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Effects of self-radiation damage on electronic properties of {sup 244}Cm{sup 3+} in an orthophosphate crystal of YPO{sub 4}

Electronic energy level of alpha-emitting isotope {sup 244}Cm{sup 3+} (t{sub {1/2}}=18.1 y) doped into single crystals of YPO{sub 4} has been studied using site-selected laser spectroscopic methods. Electronic transitions between the nominal {sup 8}S{sub 7/2} state of Cm{sup 3+} were utilized to characterize the effects of alpha-decay induced structural damage. The total splitting of the four crystal field doublets in the ground multiplet is 12.5 cm{sup -1} and that of the excited multiplet is … more

Date: October 1, 1997

Creator: Liu, G. K.; Li, S. T.; Beitz, J. V. & Abraham, M. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Molecular dynamics simulation of local structure and vibrational spectrum of uranyl (UO{sub 2}){sup 2+} in vitreous B{sub 2}O{sub 3}.

Laser spectroscopic and extended X-ray absorption fine structure (EXAFS) spectra have shown that uranium in B{sub 2}O{sub 3} glass matrix forms uranyl in the electronic configuration of (UO{sub 2}){sup 2+},but its surrounding structure is not well known. Understanding of uranyl local structure, ion-ligand interaction, and chemical stability on the nanometer scale in glasses is essential in management of long-term performance of high-level nuclear wastes after disposal in a geologic repository. … more

Date: November 3, 2000

Creator: Zhuang, Z.-H.; Liu, G. K. & Beitz, J. V.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Molecular dynamics simulation of lattice structure, radiation damage, and vibrational spectra of zircon (ZrSiO{sub 4}).

The lattice structure, phonon density of states, and infrared spectrum for crystalline zircon, ZrSiO{sub 4}, have been studied using a molecular dynamics (MD) simulation method that utilizes the Born-Mayer-Huggins and Coulomb pair potentials and the Stillinger-Weber three-body potential. A lattice block of ZrSiO{sub 4}, which contains 343 unit cells with dimensions of 4.6249 x 4.6249 x 4.1874 nm{sub 3} and containing 8232 ions, was considered in our calculations. The simulated lattice structure… more

Date: November 3, 2000

Creator: Liu, G. K.; Zhuang, H.-Z. & Beitz, J. V.

Item Type: Article

Partner: UNT Libraries Government Documents Department