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Relativistic multireference many-body perturbation theory calculations on Au64+ - Au69+ ions

Description: Many-body perturbation theory (MBPT) calculations are an adequate tool for the description of the structure of highly charged multi-electron ions and for the analysis of their spectra. They demonstrate this by way of a re-investigation of n=3, {Delta}n=0 transitions in the EUV spectra of Na-, Mg-, Al-like, and Si-like ions of Au that have been obtained previously by heavy-ion accelerator based beam-foil spectroscopy. They discuss the evidence and propose several revisions on the basis of the multi-reference many-body perturbation theory calculations of Ne- through P-like ions of Au.
Date: March 31, 2006
Creator: Vilkas, M J; Ishikawa, Y & Trabert, E
Partner: UNT Libraries Government Documents Department

Detection of Biological Materials Using Ion Mobility Spectroscopy

Description: Traditionally, Ion Mobility Spectroscopy has been used to examine ions of relatively low molecular weight and high ion mobility. In recent years, however, biomolecules such as bradykinin, cytochrome c, bovine pancreatic trypsin inhibitor (BPTI), apomyoglobin, and lysozyme, have been successfully analyzed, but studies of whole bio-organisms have not been performed. In this study an attempt was made to detect and measure the mobility of two bacteriophages, {lambda}-phage and MS2 using electrospray methods to inject the viruses into the ion mobility spectrometer. Using data from Yeh, et al., which makes a comparison between the diameter of non-biologic particles and the specific particle mobility, the particle mobility for the MS2 virus was estimated to be 10{sup {minus}2} cm{sup 2}/volt-sec. From this mobility the drift time of these particles in our spectrometer was calculated to be approximately 65 msec. The particle mobility for the {lambda}-phage virus was estimated to be 10{sup {minus}3} cm{sup 2}/volt-sec. which would result in a drift time of 0.7 sec. Spectra showing the presence of a viral peak at the expected drift time were not observed. However, changes in the reactant ion peak that could be directly attributed to the presence of the viruses were observed. Virus clustering, excessive collisions, and the electrospray injection method limited the performance of this IMS. However, we believe that an instrument specifically designed to analyze such bioagents and utilizing other injection and ionization methods will succeed in directly detecting viruses and bacteria.
Date: March 1, 1999
Creator: Rodacy, P.J.; Sterling, J.P. & Butler, M.A.
Partner: UNT Libraries Government Documents Department

Multiphoton ionization of ions, neutrals, and clusters. Progress report

Description: Scientific results are summarized from a three year research program on multiphoton ionization in aromatic molecules, clusters, and their ions. As originally proposed, the studies elucidated a new cluster ionization mechanism, characterized properties of long range intermolecular interactions, and investigated electronic transitions of aromatic cations cooled in a supersonic beam. The studies indicate that the new cluster ionization mechanism is highly efficient and dominates conventional 1 + 1 resonant ionization. In the case of the dimer of the large aromatic molecule fluorene, the results suggest that excimer formation competes with a direct ionization process. Highly selective excitonic spectra have been identified for several cluster species.
Date: June 28, 1991
Creator: Wessel, J.
Partner: UNT Libraries Government Documents Department

Ion dip spectroscopy of cold molecules and ions. Progress report and renewal proposal

Description: A research program is underway with the objective of developing techniques of high resolution multiphoton spectroscopy for selective, ultrasensitive molecular detection. Methods under study include various forms of ion dip spectroscopy and new methods of ion fragmentation spectroscopy. The studies are providing a new understanding of the fundamental spectroscopy and photophysics of large molecular ions. Dimer and cluster ions of polynuclear aromatics and related species are also being investigated, with potential detection applications.
Date: August 13, 1987
Creator: Wessel, J.
Partner: UNT Libraries Government Documents Department

Multiphoton ionization of ions, neutrals, and clusters. Final report

Description: A multiyear research program investigating molecular detection methods based on multiphoton spectroscopy has been completed under DOE sponsorship. A number of new laser-based spectroscopic methods were developed and applied to a variety of aromatic hydrocarbons, including monomer and cluster species. The objectives of sensitivities approaching single molecule detection combined with high selectivity were achieved. This report references the status of the field at the beginning of this work and summarizes the significant progress during the period from 1987 onward. Detailed scientific findings from the studies are presented in the published literature referenced throughout this report.
Date: December 28, 1995
Creator: Wessel, J.
Partner: UNT Libraries Government Documents Department

Molecular detection using Rydberg, autoionizing, and cluster states. Progress report

Description: The author reports on investigations of multiphoton ionization spectroscopy in pure clusters of aromatic molecules and mixed clusters of an aromatic molecule with a rare gas atom. Conditions needed for efficient production of ion clusters are discussed. Experimental results that establish geometry of naphthalene and benzene clusters are described.
Date: August 15, 1990
Creator: Wessel, J.
Partner: UNT Libraries Government Documents Department

Resonance ionization spectroscopy of molecules, clusters, and ions. Annual technical progress report

Description: High resolution photoionization and fluorescence excitation spectra of dimers of the aromatic molecule fluorene (C{sub 13}H{sub 12}){sub 2} reveal complex excitonic interactions. Comparison of results for isotopically pure and isotopically mixed dimers provide the information necessary to analyze the spectra in terms of intermolecular motion on two perturbed adiabatic potential surfaces. The intermolecular force field on the lower surface is characterized by a perturbed quartic potential, whereas the upper surface is characterized by a displaced quadratic potential. The results provide the first detailed experimental description of strong coupling between an intermolecular coordinate and the excitonic state of a molecular dimer.
Date: July 14, 1993
Creator: Wessel, J.
Partner: UNT Libraries Government Documents Department

Surface analysis of all elements with isotopic resolution at high ambient pressures using ion spectroscopic techniques

Description: The authors have developed a mass spectrometer capable of surface analysis using the techniques of secondary ion mass spectroscopy (SIMS) and mass spectroscopy of recoiled ions (MSRI). For SIMS, an energetic ion beam creates a collision cascade which results in the ejection of low kinetic energy secondary ions from the surface being analyzed. The low kinetic energy SIMS ions are very susceptible to charge neutralization with the surface, and as a result, the SIMS ion yield varies by orders of magnitude depending on the chemical state of the surface. SIM spectra contain elemental ions, and molecular ions. For MSRI, a pulsed ion beam induces a binary collision with the surface being analyzed and the surface species are recoiled into the forward scattering direction with a large kinetic energy. The violence of the binary collision results in complete molecular decomposition, and only elemental ions are detected. The high kinetic energy MSRI ions are much less susceptible to charge neutralization with the surface than the low kinetic energy SIMS ions. In MSRI, the ion yield typically varies by less than a factor of ten as the chemical state of the surface changes--simplifying quantitative analysis vs. SIMS. In this paper, they authors will demonstrate that the high kinetic energy MSRI ions are able to transverse high pressure paths with only a reduction in peak intensity--making MSRI an ideal tool for real-time, in-situ film growth studies. The use of a single analyzer for both MSRI and SIMS is unique and provides complimentary information.
Date: September 1, 1997
Creator: Smentkowski, V.S.; Krauss, A.R.; Gruen, D.M.; Holecek, J.C. & Schultz, J.A.
Partner: UNT Libraries Government Documents Department

Resonance ionization spectroscopy of molecules, clusters, and ions. Continuation proposal and annual technical progress report

Description: Supersonic beam studies of the dimer of the aromatic molecule fluorene reveal both excitonic and excimer properties. The high resolution spectra obtained for the cold clusters suggests that it will be possible to elucidate the coupling between these types of states. The accumulating evidence indicates that both types of states occur generally for aromatic clusters. Their relative contributions to the spectra are not currently understood. This problem is the emphasis of the ongoing investigations. Future work will address the intermolecular potential functions of these species in increasing detail.
Date: July 10, 1992
Creator: Wessel, J.
Partner: UNT Libraries Government Documents Department

Molecular detection using Rydberg, autoionizing, and cluster states. Progress report

Description: Continuing investigations of multiphoton ionization processes in naphthalene have established the geometry and spectroscopy of trimer and tetramer cluster states. A new, highly efficient ionization mechanism has been identified in the trimer. It is closely related to autoionization of 2-electron atoms by resonant 2-photon excitation and to exciton fusion in larger clusters.
Date: August 17, 1989
Creator: Wessel, J.
Partner: UNT Libraries Government Documents Department

Ion dip spectroscopy of cold molecules and ions. Progress report

Description: During the past year, the main emphasis in this research program has been on multiphoton ionization spectroscopy of aromatic clusters. This is being pursued in addition to continuing work in areas of ion dip spectroscopy and ion fragmentation spectroscopy. The program has the overall objective of developing improved ultrasensitive molecular detection methods based on multiphoton laser spectroscopy. Photoionization techniques are employed due to their extreme sensitivity combined with mass selectivity. The combination of these two features has led to the current capability to study molecular clusters of specific sizes with high spectral resolution. Clusters are formed in abundance in a supersonic expansion, where they are excited and ionized by an ultraviolet laser beam. The studies reported here are principally based on simple resonant excitation of clusters, followed by one-photon ionization. For the naphthalene clusters, a single laser wavelength suffices for both excitation steps. Additional investigations have been carried out to measure excited state cluster ionization spectra and cluster ion fragmentation spectra. Results from these measurements are not yet sufficiently advanced to report in detail, however the preliminary data support the importance of recently proposed new fundamental ionization mechanisms in clusters. This brief report summarizes results described in more detail in the preprint titled: Resonant two-photon ionization spectroscopy of naphthalene clusters and the preprint titled: Resonance interactions in naphthalene clusters. It also briefly describes preliminary undisclosed results of current investigations.
Date: August 23, 1988
Creator: Wessel, J.E.
Partner: UNT Libraries Government Documents Department

Ulysses solar wind plasma observations from peak southerly latitude through perihelion and beyond

Description: We present Ulysses solar wind plasma data from the peak southerly latitude of {minus}80.2{degrees} through +64.9{degrees} latitude on June 7, 1995. Ulysses encountered fast wind throughout this time except for a 43{degrees} band centered on the solar equator. Median mass flux was nearly constant with latitude, while speed and density had positive and negative poleward gradients, respectively. Solar wind momentum flux was highest at high latitudes, suggesting a latitudinal asymmetry in the heliopause cross section. Solar wind energy flux density was also highest at high latitudes.
Date: September 1, 1995
Creator: Phillips, J.L.; Bame, S.J.; Feldman, W.C.; Gosling, J.T.; McComas, D.J.; Goldstein, B.E. et al.
Partner: UNT Libraries Government Documents Department

Autoionizing states in highly ionized oxygen, fluorine and silicon

Description: Autoionizing states in high Z 3-electron ions associated with core excited configurations of the type 1s2snl and 1s2pnl are reported. The electron decay-in-flight spectra of lithium-like oxygen, fluorine, and silicon ions are presented. Initial beam energies of 6.75-MeV oxygen and fluorine ions and 22.5- MeV silicon ions were used. Stripping and excitation were done by passing the beams through a thin carbon foil. The experimental technique is described. 4 figs, 1 table, 7 refs. (GHT)
Date: January 1, 1975
Creator: Forester, J.P.; Peterson, R.S.; Griffin, P.M.; Pegg, D.J.; Haselton, H.H.; Liao, K.H. et al.
Partner: UNT Libraries Government Documents Department

Single Ion Trapping for the Enriched Xenon Observatory

Description: In the last decade, a variety of neutrino oscillation experiments have established that there is a mass difference between neutrino flavors, without determining the absolute neutrino mass scale. The Enriched Xenon Observatory for neutrinoless double beta decay (EXO) will search for the rare decays of xenon to determine the absolute value of the neutrino mass. The experiment uses a novel technique to minimize backgrounds, identifying the decay daughter product in real time using single ion spectroscopy. Here, we describe single ion trapping and spectroscopy compatible with the EXO detector. We extend the technique of single ion trapping in ultrahigh vacuum to trapping in xenon gas. With this technique, EXO will achieve a neutrino mass sensitivity of <m{sub {nu}}> {approx_equal} .010 eV.
Date: March 28, 2006
Creator: Waldman, Samuel J. & /Stanford U., Phys. Dept. /SLAC
Partner: UNT Libraries Government Documents Department

A velocity map imaging spectrometer for electron?ion and ion?ion coincidence experiments with synchrotron radiation

Description: We have built a velocity imaging (VMI) spectrometer optimized for angle-resolved photoionization experiments with synchrotron radiation (SR) in the VUV and soft X-tay range. The spectrometer is equiped with four electrostatic lenses that focus the charged photoionization products onto a position-sensitive multi-hit delay-line anode. The use of two additional electrostatic lens elements as compared to the standard design of Eppink and Parker [T.J.B. Eppink and D.H. Parker, Rev. Sci. Instrum. 68 (1997) 3477]provides better focusing of an extended interaction region, which is crucial for most SR applications. Furthermore, the apparatus is equipped with a second micro-channel plate detector opposite to the VMI spectrometer, enabling electron-ion coincidence experiments and thereby mass-resolved ion spectroscopy independent of the time structure of the synchrotron radiation. First results for the photofragmentation of CO2 molecules are presented.
Date: April 27, 2007
Creator: Lawrence Berkeley National Laboratory. Advanced Light Source.
Partner: UNT Libraries Government Documents Department

Field screening of soils contaminated with explosives using ion mobility spectrometry

Description: This study involved the comparison of IMS screening with EPA`s standard method for explosives, Method 8330. The US Army Corps of Engineers provided a large number of soil samples that had been collected from three locations at each of three explosive contaminated installations. The samples had been dried, ground, homogenized and analyzed in duplicate by Method 8330. Duplicate two gram aliquots of these samples were extracted with 10 mL of acetone by shaking for three minutes, allowed to settle, then analyzed by IMS for Method 8330 compounds. Half of the extracts from one location have also been analyzed in duplicate by IMS for TNT. Results from TNT contaminated soils look extremely promising. Correlation between IMS and EPA Method 8330 results was very high (r = 0.99). Based on these results, the intention is to further develop and evaluate IMS for simultaneously quantifying multiple analytes. IMS throughput and cost per sample makes it an attractive technique. The ultimate objective is to provide adequate validation data to EPA for inclusion of the method as a screening procedure in SW-846.
Date: May 1, 1997
Creator: Atkinson, D.A.; Crockett, A.B. & Jenkins, T.F.
Partner: UNT Libraries Government Documents Department

Field screening of soils contaminated with explosives using ion mobility spectrometry

Description: Soils contaminated with explosives constitute a problem at DOE facilities and Army installations. Because explosives in soil are often heterogeneously distributed and require high density sampling, field screening is essential to characterize sites more quickly, economically and accurately. Current immunoassay and colorimetric field screening procedures have proven useful, but have significant per sample costs and limited throughput. At present, several field screening are available for TNT in soil, three procedures for RDX, and one procedure for 2,4-DNTand ammonium picrate/picric acid (AP/PA). Ion mobility spectrometry (IMS) has been used to detect explosives in air at ppt levels, but limited work has been done to apply the technique to quantify explosives in soils. The objective of this study has been to evaluate the utility of IMS as a screening technique for quantifying explosive residues in soils.
Date: September 1, 1996
Creator: Crockett, A.B.; Atkinson, D.A. & Jenkins, T.F.
Partner: UNT Libraries Government Documents Department

Using heavy ion backscattering spectrometry (HIBS) to solve integrated circuit manufacturing problems

Description: Heavy Ion Backscattering Spectrometry (HIBS) is a new IBA tool for measuring extremely low levels of surface contamination on very pure substrates, such as Si wafers used in the manufacture of integrated circuits. HIBS derives its high sensitivity through the use of moderately low energy ({approximately} 100 keV) heavy ions (e.g., C{sup 12}) to boost the RBS cross-section to levels approaching 1,000 barns, and by using specially designed time-of-flight detectors which have been optimized to provide a large scattering solid angle with minimal kinematic broadening. A HIBS User Facility has been created which provides US industry, national laboratories, and universities with a place for conducting ultra-trace level surface contamination studies. A review of the HIBS technique is given and examples of using the facility to calibrate Total-Reflection X-ray Fluorescence Spectroscopy (TXRF) instruments and develop wafer cleaning processes are discussed.
Date: December 1, 1997
Creator: Banks, J.C.; Doyle, B.L.; Knapp, J.A.; Werho, D.; Gregory, R.B.; Anthony, M. et al.
Partner: UNT Libraries Government Documents Department

In-situ, real-time, studies of film growth processes using ion scattering and direct recoil spectroscopy techniques.

Description: Time-of-flight ion scattering and recoil spectroscopy (TOF-ISARS) enables the characterization of the composition and structure of surfaces with 1-2 monolayer specificity. It will be shown that surface analysis is possible at ambient pressures greater than 3 mTorr using TOF-ISARS techniques; allowing for real-time, in situ studies of film growth processes. TOF-ISARS comprises three analytical techniques: ion scattering spectroscopy (ISS), which detects the backscattered primary ion beam; direct recoil spectroscopy (DRS), which detects the surface species recoiled into the forward scattering direction; and mass spectroscopy of recoiled ions (MSRI), which is 3 variant of DRS capable of isotopic resolution for all surface species--including H and He. The advantages and limitations of each of these techniques will be discussed. The use of the three TOF-ISARS methods for real-time, in situ film growth studies at high ambient pressures will be illustrated. It will be shown that MSRI analysis is possible during sputter deposition. It will be also be demonstrated that the analyzer used for MSRI can also be used for time of flight secondary ion mass spectroscopy (TOF-SIMS) under high vacuum conditions. The use of a single analyzer to perform the complimentary surface analytical techniques of MSRI and SIMS is unique. The dwd functionality of the MSRI analyzer provides surface information not obtained when either MSRI or SIMS is used independently.
Date: April 22, 1999
Creator: Smentkowski, V. S.
Partner: UNT Libraries Government Documents Department

Evaluation and analysis of non-intrusive techniques for detecting illicit substances

Description: Argonne National Laboratory (ANL) and the Houston Advanced Research Center (HARC) have been tasked by the Counterdrug Technology Assessment Center of the Office of National Drug Control Policy to conduct evaluations and analyses of technologies for the non-intrusive inspection of containers for illicit substances. These technologies span the range of nuclear, X-ray, and chemical techniques used in nondestructive sample analysis. ANL has performed assessments of nuclear and X-ray inspection concepts and undertaken site visits with developers to understand the capabilities and the range of applicability of candidate systems. ANL and HARC have provided support to law enforcement agencies (LEAs), including participation in numerous field studies. Both labs have provided staff to assist in the Narcotics Detection Technology Assessment (NDTA) program for evaluating drug detection systems. Also, the two labs are performing studies of drug contamination of currency. HARC has directed technical evaluations of automated ballistics imaging and identification systems under consideration by law enforcement agencies. ANL and HARC have sponsored workshops and a symposium, and are participating in a Non-Intrusive Inspection Study being led by Dynamics Technology, Incorporated.
Date: December 31, 1995
Creator: Micklich, B.J.; Roche, C.T.; Fink, C.L.; Yule, T.J.; Demirgian, J.C.; Kunz, T.D. et al.
Partner: UNT Libraries Government Documents Department

Fourier transform ion cyclotron resonance precision atomic mass measurement limits

Description: The application of Fourier Transform Ion Cylcotron Resonance Mass Spectroscopy to precision atomic mass measurements is considered. Limits on the mass accuracy of this technique for atomic masses are discussed, and plans for future developments with application to fundamental weak interaction physics are presented.
Date: July 1, 1992
Creator: Kouzes, R.T.
Partner: UNT Libraries Government Documents Department

Model ion abundances for comet Halley

Description: A computer model for comet comae has been applied to predict ion abundances for comet Halley. It is assumed that the volatile component of the nucleus is 85% water and that the remaining volatile molecules are composed of carbon, nitrogen, oxygen, and sulfur. Model parameters such as heliocentric distance, size, and albedo are chosen to be consistent with the 13-14 March 1986 encounter of the Giotto spacecraft with the comet. Photoprocesses, gas-phase chemical kinetics, coma energy balance including a separate electron temperature, multifluid hydrodynamics with a transition to free molecular flow, fast streaming atomic and molecular hydrogen, and counter and cross streaming of species in the coma-solar wind interaction are taken into consideration. A comparison of the model results is made with preliminary data from the ion mass spectrometer at 6000 and 1500 km from the nucleus. We find good overall agreement. The implications of the coma physics and chemistry are discussed. 2 tabs.
Date: October 27, 1986
Creator: Huebner, W.F.; Boice, D.C.; Keady, J.J.; Schmidt, H.U. & Wegman, R.
Partner: UNT Libraries Government Documents Department

Experiments on few-electron very high-Z ions

Description: The measurement of the Lamb shift in heliumlike uranium and outlines future experimental tests of QED using few-electron very high atomic number (Z) ions are presented. A discussion of the possibility of using ultrarelativistic atomic collisions to produce very heavy leptons is also presented. 38 refs., 4 figs., 1 tab.
Date: July 1, 1986
Creator: Gould, H. & Munger, C.
Partner: UNT Libraries Government Documents Department

Tests of quantum electrodynamics in few-electron very high-Z ions

Description: This article discusses our measurement of the Lamb shift in heliumlike uranium and outlines future tests of QED using few- electron very high atomic number (Z) ions. Our recently reported Lamb shift value of 70.4 (8.1) eV for the one- electron Lamb shift in uranium is in agreement with the theoretical value of 75.3 (0.4) eV. The experimental value was extracted from a beam-foil time-of-flight measurement of the 54.4 (3.3) ps lifetime of the 1s2p/sub 1/2/ /sup 3/P/sub 0/ state of heliumlike uranium. 24 refs., 5 figs., 1 tab.
Date: August 1, 1986
Creator: Gould, H. & Munger, C.T.
Partner: UNT Libraries Government Documents Department