Recent U.S. advances in ion-beam-driven high energy densityphysics and heavy ion fusion (open access)

Recent U.S. advances in ion-beam-driven high energy densityphysics and heavy ion fusion

During the past two years, significant experimental and theoretical progress has been made in the US heavy ion fusion science program in longitudinal beam compression, ion-beam-driven warm dense matter, beam acceleration, high brightness beam transport; and advanced theory and numerical simulations. Innovations in longitudinal compression of intense ion beams by > 50 X propagating through background plasma enable initial beam target experiments in warm dense matter to begin within the next two years. They are assessing how these new techniques might apply to heavy ion fusion drivers for inertial fusion energy.
Date: July 5, 2006
Creator: Logan, B. G.; Bieniosek, F. M.; Celata, C. M.; Coleman, J.; Greenway, W.; Henestroza, E. et al.
System: The UNT Digital Library
Optical Properties in Non-equilibrium Phase Transitions (open access)

Optical Properties in Non-equilibrium Phase Transitions

An open question about the dynamical behavior of materials is how phase transition occurs in highly non-equilibrium systems. One important class of study is the excitation of a solid by an ultrafast, intense laser. The preferential heating of electrons by the laser field gives rise to initial states dominated by hot electrons in a cold lattice. Using a femtosecond laser pump-probe approach, we have followed the temporal evolution of the optical properties of such a system. The results show interesting correlation to non-thermal melting and lattice disordering processes. They also reveal a liquid-plasma transition when the lattice energy density reaches a critical value.
Date: January 5, 2006
Creator: Ao, T; Ping, Y; Widmann, K; Price, D F; Lee, E; Tam, H et al.
System: The UNT Digital Library
Approaches to Beam Stabilization in X-Band Linear Colliders (open access)

Approaches to Beam Stabilization in X-Band Linear Colliders

In order to stabilize the beams at the interaction point, the X-band linear collider proposes to use a combination of techniques: inter-train and intra-train beam-beam feedback, passive vibration isolation, and active vibration stabilization based on either accelerometers or laser interferometers. These systems operate in a technologically redundant fashion: simulations indicate that if one technique proves unusable in the final machine, the others will still support adequate luminosity. Experiments underway for all of these technologies have already demonstrated adequate performance.
Date: September 5, 2006
Creator: Frisch, Josef; Hendrickson, Linda; Himel, Thomas; Markiewicz, Thomas; Raubenheimer, Tor; Seryi, Andrei et al.
System: The UNT Digital Library
Gas Centrifuge Enrichment Plant Safeguards System Modeling (open access)

Gas Centrifuge Enrichment Plant Safeguards System Modeling

None
Date: July 5, 2006
Creator: Elayat, H A; O'Connell, W J & Boyer, B D
System: The UNT Digital Library
Measurement of the Pseudoscalar Decay Constantf_D_s Using Charm-Tagged Events in e+e- Collisions atsqrt{s}=10.58 GeV (open access)

Measurement of the Pseudoscalar Decay Constantf_D_s Using Charm-Tagged Events in e+e- Collisions atsqrt{s}=10.58 GeV

Using 230.2 fb{sup -1} of e{sup +}e{sup -} annihilation data collected with the BABAR detector at and near the peak of the {Upsilon}(4S) resonance, 489 {+-} 55 events containing the pure leptonic decay D{sub s}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}} have been isolated in charm-tagged events. The ratio of partial widths {Lambda}(D{sub s}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}})/{Lambda}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}) is measured to be 0.143 {+-} 0.018 {+-} 0.006 allowing a determination of the pseudoscalar decay constant f{sub D{sub 2}} = (283 {+-} 17 {+-} 7 {+-} 14) MeV. The errors are statistical, systematic, and from the D{sub s}{sup +} {yields} {phi}{pi}{sup +} branching ratio, respectively.
Date: September 5, 2006
Creator: Aubert, B.
System: The UNT Digital Library
Measurements of |V_{cb}| and |V_{ub}| at BaBar (open access)

Measurements of |V_{cb}| and |V_{ub}| at BaBar

We report on new measurements of the Cabibbo-Kobayashi-Maskawa matrix elements |V{sub cb}| and |V{sub ub}| with inclusive and exclusive semileptonic B decays, highlighting the recent precision measurements with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC.
Date: January 5, 2006
Creator: Godang, Romulus & U., /Mississippi
System: The UNT Digital Library
Potential Flammable Gas Explosion in the TRU Vent and Purge Machine (open access)

Potential Flammable Gas Explosion in the TRU Vent and Purge Machine

The objective of the analysis was to determine the failure of the Vent and Purge (V&P) Machine due to potential explosion in the Transuranic (TRU) drum during its venting and/or subsequent explosion in the V&P machine from the flammable gases (e.g., hydrogen and Volatile Organic Compounds [VOCs]) vented into the V&P machine from the TRU drum. The analysis considers: (a) increase in the pressure in the V&P cabinet from the original deflagration in the TRU drum including lid ejection, (b) pressure wave impact from TRU drum failure, and (c) secondary burns or deflagrations resulting from excess, unburned gases in the cabinet area. A variety of cases were considered that maximized the pressure produced in the V&P cabinet. Also, cases were analyzed that maximized the shock wave pressure in the cabinet from TRU drum failure. The calculations were performed for various initial drum pressures (e.g., 1.5 and 6 psig) for 55 gallon TRU drum. The calculated peak cabinet pressures ranged from 16 psig to 50 psig for various flammable gas compositions. The blast on top of cabinet and in outlet duct ranged from 50 psig to 63 psig and 12 psig to 16 psig, respectively, for various flammable gas compositions. The …
Date: April 5, 2006
Creator: Vincent, A
System: The UNT Digital Library
Towards the NNLL Precision in the Decay $\bar B \rightarrow X_s \gamma$ (open access)

Towards the NNLL Precision in the Decay $\bar B \rightarrow X_s \gamma$

The present NLL prediction for the decay rate of the rare inclusive process {bar B} {yields} X{sub s}{gamma} has a large uncertainty due to the charm mass renormalization scheme ambiguity. We estimate that this uncertainty will be reduced by a factor of 2 at the NNLL level. This is a strong motivation for the on-going NNLL calculation, which will thus significantly increase the sensitivity of the observable {bar B} {yields} X{sub s}{gamma} to possible new degrees of freedom beyond the SM. We also give a brief status report of the NNLL calculation.
Date: January 5, 2006
Creator: Asatrian, Hrachia M.; Hovhannisyan, Artyom; Poghosyan, Vahagn; Inst., /Yerevan Phys.; Greub, Christoph; U., /Bern et al.
System: The UNT Digital Library
A New HOM Water Cooled Absorber for the PEP-II B-factory Low Energy Ring (open access)

A New HOM Water Cooled Absorber for the PEP-II B-factory Low Energy Ring

At high currents and small bunch lengths beam line components in the PEP-II B-factory experience RF induced heating from higher order RF modes (HOMs) produced by scattered intense beam fields. A design for a passive HOM water cooled absorber for the PEP-II low energy ring is presented. This device is situated near HOM producing beamline components such as collimators and provide HOM damping for dipole and quadrupole modes without impacting beam impedance. We optimized the impedance characteristics of the device through the evaluation of absorber effectiveness for specific modes using scattering parameter and wakefield analysis. Operational results are presented and agree very well with the predicted effectiveness.
Date: September 5, 2006
Creator: Weathersby, Stephen; Kosovsky, Michael; Kurita, Nadine; Novokhatski, Alexander & Seeman, John
System: The UNT Digital Library
Measurements of the Branching Fractions and CP Asymmetries of B -> D0_CP K Decays (open access)

Measurements of the Branching Fractions and CP Asymmetries of B -> D0_CP K Decays

We present a study of the decay B{sup -} {yields} D{sub (CP)}{sup 0} K{sup -} and its charge conjugate, where D{sub (CP)}{sup 0} is reconstructed in CP-even, CP-odd, and non-CP flavor eigenstates, based on a sample of 232 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring. We measure the partial-rate charge asymmetries AC{sub CP{+-}} and the ratios R{sub CP{+-}} of the B {yields} D{sup 0} K decay branching fractions as measured in CP{+-} and non-CP D{sup 0} decays: A{sub CP+} = 0.35 {+-} 0.13(stat) {+-} 0.04(syst), A{sub CP-} = -0.06 {+-} 0.13(stat) {+-} 0.04(syst), R{sub CP+} = 0.90 {+-} 0.12(stat) {+-} 0.04(syst), R{sub CP-} = 0.86 {+-} 0.10(stat) {+-} 0.05(syst).
Date: January 5, 2006
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
System: The UNT Digital Library
Optics of the ILC Extraction Line for 2mrad Crossing Angle (open access)

Optics of the ILC Extraction Line for 2mrad Crossing Angle

The ILC extraction line for 2 mrad crossing angle is under development by the SLAC-BNL-UK-France task force collaboration. This report describes the progress in the 2 mrad optics design which includes the changes to the final focus doublet, the complete optics for the extraction diagnostics, and the changes to the sextupole and collimation systems. The results of disrupted beam tracking simulations are presented.
Date: January 5, 2006
Creator: Nosochkov, Y.; Moffeit, K.; Seryi, A.; Spencer, C.; Woods, M.; Angal-Kalinin, D. et al.
System: The UNT Digital Library
The GLAST Mission, LAT and GRBs (open access)

The GLAST Mission, LAT and GRBs

The GLAST Large Area Telescope (LAT) is the next generation satellite experiment for high-energy gamma-ray astronomy. It is a pair conversion telescope built with a plastic anticoincidence shield, a segmented CsI electromagnetic calorimeter, and the largest silicon strip tracker ever built. It will cover the energy range from 30 MeV to 300 GeV, shedding light on many issues left open by its predecessor EGRET. One of the most exciting science topics is the detection and observation of gamma-ray bursts (GRBs). In this paper we present the work done so far by the GRB LAT science group in studying the performance of the LAT detector to observe GRBs.We report on the simulation framework developed by the group as well as on the science tools dedicated to GRBs data analysis. We present the LAT sensitivity to GRBs obtained with such simulations, and, finally, the general scheme of GRBs detection that will be adopted on orbit.
Date: April 5, 2006
Creator: Omodei, Nicola
System: The UNT Digital Library
FAST NEUTRON COVARIANCES FOR EVALUATED DATA FILES. (open access)

FAST NEUTRON COVARIANCES FOR EVALUATED DATA FILES.

We describe implementation of the KALMAN code in the EMPIRE system and present first covariance data generated for Gd and Ir isotopes. A complete set of covariances, in the full energy range, was produced for the chain of 8 Gadolinium isotopes for total, elastic, capture, total inelastic (MT=4), (n,2n), (n,p) and (n,alpha) reactions. Our correlation matrices, based on combination of model calculations and experimental data, are characterized by positive mid-range and negative long-range correlations. They differ from the model-generated covariances that tend to show strong positive long-range correlations and those determined solely from experimental data that result in nearly diagonal matrices. We have studied shapes of correlation matrices obtained in the calculations and interpreted them in terms of the underlying reaction models. An important result of this study is the prediction of narrow energy ranges with extremely small uncertainties for certain reactions (e.g., total and elastic).
Date: June 5, 2006
Creator: HERMAN, M.; OBLOZINSKY, P.; ROCHMAN, D.; KAWANO, T. & LEAL, L.
System: The UNT Digital Library
FR-II Broad Absorption Line Quasars and the Life Cycle of Quasars (open access)

FR-II Broad Absorption Line Quasars and the Life Cycle of Quasars

By combining the Sloan Digitized Sky Survey Third Data Release quasar list with the VLA FIRST survey, we have identified five objects having both broad absorption lines in their optical spectra and FR-II radio morphologies. We identify an additional example of this class from the FIRST Bright Quasar Survey, J1408+3054. Including the original FR-II-BAL object, J1016+5209, brings the number of such objects to eight. These quasars are relatively rare; finding this small handful has required the 45,000-large quasar sample of SDSS. The FR-II-BAL quasars exhibit a significant anti-correlation between radio-loudness and the strength of the BAL features. This is easily accounted for by the evolutionary picture in which quasars emerge from cocoons of BAL-producing material which stifle the development of radio jets and lobes. There is no such simple explanation for the observed properties of FR-II-BALs in the unification-by-orientation model of quasars. The rarity of the FR-II-BAL class implies that the two phases do not coexist for very long in a single quasar, perhaps less than 10{sup 5} years, with the combined FR-II, high ionization broad absorption phase being even shorter by another factor of 10 or more.
Date: January 5, 2006
Creator: Gregg, M D; Becker, R H & de Vries, W
System: The UNT Digital Library
Gas Centrifuge Enrichment Plant Safeguards System Modeling (open access)

Gas Centrifuge Enrichment Plant Safeguards System Modeling

The U.S. Department of Energy (DOE) is interested in developing tools and methods for potential U.S. use in designing and evaluating safeguards systems used in enrichment facilities. This research focuses on analyzing the effectiveness of the safeguards in protecting against the range of safeguards concerns for enrichment plants, including diversion of attractive material and unauthorized modes of use. We developed an Extend simulation model for a generic medium-sized centrifuge enrichment plant. We modeled the material flow in normal operation, plant operational upset modes, and selected diversion scenarios, for selected safeguards systems. Simulation modeling is used to analyze both authorized and unauthorized use of a plant and the flow of safeguards information. Simulation tracks the movement of materials and isotopes, identifies the signatures of unauthorized use, tracks the flow and compilation of safeguards data, and evaluates the effectiveness of the safeguards system in detecting misuse signatures. The simulation model developed could be of use to the International Atomic Energy Agency IAEA, enabling the IAEA to observe and draw conclusions that uranium enrichment facilities are being used only within authorized limits for peaceful uses of nuclear energy. It will evaluate improved approaches to nonproliferation concerns, facilitating deployment of enhanced and cost-effective safeguards …
Date: June 5, 2006
Creator: Elayat, H A; O'Connell, W J & Boyer, B D
System: The UNT Digital Library
Is it Worth it? A Comparative Analysis of Cost-Benefit Projectionsfor State Renewables Portfolio Standards (open access)

Is it Worth it? A Comparative Analysis of Cost-Benefit Projectionsfor State Renewables Portfolio Standards

State renewables portfolio standards (RPS) have emerged as one of the most important policy drivers of renewable energy capacity expansion in the U.S. Collectively, these policies now apply to almost 40% of U.S. electricity load, and may have substantial impacts on electricity markets, ratepayers, and local economies. As RPS policies have been proposed or adopted in an increasing number of states, a growing number of studies have attempted to quantify the potential impacts of these policies, focusing primarily on projecting cost impacts, but sometimes also estimating macroeconomic and environmental effects. This report synthesizes and analyzes the results and methodologies of twenty-six distinct state or utility-level RPS cost impact analyses completed since 1998 (see Figure 1 and Appendix for a complete list of the studies). Together, these studies model proposed or adopted RPS policies in seventeen different states. We highlight the key findings of these studies on the costs and benefits of RPS policies, examine the sensitivity of projected costs to model assumptions, assess the attributes of different modeling approaches, and suggest possible areas of improvement for future RPS analysis.
Date: June 5, 2006
Creator: Chen, Cliff; Wiser, Ryan & Bolinger, Mark
System: The UNT Digital Library
Use of Antineutrino Detectors for Nuclear Reactor Safeguards Effectiveness Assessment (open access)

Use of Antineutrino Detectors for Nuclear Reactor Safeguards Effectiveness Assessment

As described in an earlier article [1], important information regarding reactor power and the amount and type of fissile material in reactor cores can be determined by measuring the antineutrino rate and energy spectrum, using a cubic meter scale antineutrino detector at tens of meters standoff from the core. Current International Atomic Energy Agency (IAEA) safeguards techniques do not provide such real-time quantitative information regarding core power levels and isotopic composition. The possible benefits of this approach are several and have been discussed in the earlier article. One key advantage is that the method gives the inspecting agency completely independent access to real-time information on the operational status and fissile content of the core. Furthermore, the unattended and non-intrusive nature of the technology may reduce the monitoring burden on the plant operator, even though more information is being provided than is available within the current IAEA safeguards regime. Here we present a detailed analytical framework for measuring the impact that such a detector might have on IAEA safeguards, if implemented. To perform the analysis, we will use initial data from our operating detector and a standard analysis technique for safeguards regimes, developed at Lawrence Livermore National Laboratory. Because characterization of …
Date: June 5, 2006
Creator: Bernstein, A; Lambert, H E; Elayat, H A; O'Connell, W J; Rexroth, P; Baldwin, G et al.
System: The UNT Digital Library
Discovery of Ultra-Compact Dwarf Galaxies in the Virgo Cluster (open access)

Discovery of Ultra-Compact Dwarf Galaxies in the Virgo Cluster

The authors have discovered nine ultra-compact dwarf galaxies (UCDs) in the Virgo Cluster, extending samples of these objects outside the Fornax Cluster. Using the 2dF multi-fiber spectrograph on the Anglo-Australian Telescope, the new Virgo members were found among 1500 color-selected, star-like targets with 16.0 < b{sub j} < 20.2 in a two-degree diameter field centered on M87 (NGC4486). The newly-found UCDs are comparable to the UCDs in the Fornax Cluster, with sizes {approx} 100 pc, -12.9 < M{sub B} < -10.7, and exhibiting red, absorption-line spectra, indicative of an older stellar population. The properties of these objects remain consistent with the tidal threshing model for the origin of UCDs from the surviving nuclei of nucleated dwarf ellipticals disrupted in the cluster core. The discovery that UCDs exist in Virgo shows that this galaxy type is probably a ubiquitous phenomenon in clusters of galaxies; coupled with their possible origin by tidal threshing, the UCD population is a potential indicator and probe of the formation history of a given cluster. They also describe one additional bright UCD with M{sub B} = -12.0 in the core of the Fornax Cluster. They find no further UCDs in our Fornax Cluster Spectroscopic Survey down to …
Date: January 5, 2006
Creator: Jones, J.; Drinkwater, M.; Jurek, R.; Phillips, S.; Gregg, M.; Bekki, K. et al.
System: The UNT Digital Library
NUCLEAR DATABASES FOR REACTOR APPLICATIONS. (open access)

NUCLEAR DATABASES FOR REACTOR APPLICATIONS.

The National Nuclear Data Center (NNDC): An overview of nuclear databases, related products, nuclear data Web services and publications. The NNDC collects, evaluates, and disseminates nuclear physics data for basic research and applied nuclear technologies. The NNDC maintains and contributes to the nuclear reaction (ENDF, CSISRS) and nuclear structure databases along with several others databases (CapGam, MIRD, IRDF-2002) and provides coordination for the Cross Section Evaluation Working Group (CSEWG) and the US Nuclear Data Program (USNDP). The Center produces several publications and codes such as Atlas of Neutron Resonances, Nuclear Wallet Cards booklets and develops codes, such as nuclear reaction model code Empire.
Date: June 5, 2006
Creator: Pritychenko, B.; Arcilla, R.; Burrows, T.; Herman, M. W.; Mughabghab, S.; Oblozinsky, P. et al.
System: The UNT Digital Library
Modeling Efforts to Aid in the Determination of Process Enrichment Levels for Identifying Potential Material Diversion (open access)

Modeling Efforts to Aid in the Determination of Process Enrichment Levels for Identifying Potential Material Diversion

None
Date: June 5, 2006
Creator: Guenther, C. F.; Elayat, H. A. & O'Connell, W. J.
System: The UNT Digital Library
DUAL ION EXPOSURE VS. SPLIT-DOSE EXPOSURES IN HUMAN CELL NEOPLASTIC TRANSFORMATION. (open access)

DUAL ION EXPOSURE VS. SPLIT-DOSE EXPOSURES IN HUMAN CELL NEOPLASTIC TRANSFORMATION.

Since radiation fields of space contain many-fold more protons than high atomic number, high energy (HZE) particles, cells in astronaut crews will experience on average several proton hits before an HZE hit. Thus radiation regimes of proton exposure before HZE particle exposure simulate space radiation exposure, and measurement of the frequency of neoplastic transformation of human primary cells to anchorage-independent growth simulates in initial step in cancer induction. Previously our group found that exposure to 20 cGy 1 GeV/n protons followed within about 1 hr by a HZE ion (20 cGy 1 GeV/n Fe or Ti ions) hit gave about a 3-fold increase in transformation frequency ([1]). To provide insight into the H-HZE induced increased transformation frequencies, we asked if split doses of the same ion gave similar increased transformation frequencies. However, the data show that the split dose of 20 cGy plus 20 cGy of either H or HZE ions gave about the same effect as the 40 cGy uninterrupted dose, quite different from the effect of the mixed ion H + HZE irradiation. We also asked if lower proton doses than 20 cGy followed 15 minutes later by 20 cGy of HZE ions gave greater than additive transformation …
Date: June 5, 2006
Creator: BENNETT, P.V.; CUTTER, N.C. & SUTHERLAND, B.M.
System: The UNT Digital Library
Development and Characterization of a High Magnetic Field Solenoid for Laser Plasma Experiments (open access)

Development and Characterization of a High Magnetic Field Solenoid for Laser Plasma Experiments

An electromagnetic solenoid was developed to study the quenching of nonlocal heat transport in laser-produced gas-jet plasmas by high external magnetic fields. The solenoid, which is driven by a pulsed power system supplying 30 kJ, achieves fields exceeding 10 T. Temporally resolved measurements of the electron temperature profile transverse to a high power laser beam were obtained using Thomson Scattering. A method for optimizing the solenoid design based on the available stored energy is presented.
Date: May 5, 2006
Creator: Pollock, B B; Froula, D H; Davis, P F; Ross, J S; Divol, L; Fulkerson, S et al.
System: The UNT Digital Library
Phenotype Clustering of Breast Epithelial Cells in Confocal Imagesbased on Nuclear Protein Distribution Analysis (open access)

Phenotype Clustering of Breast Epithelial Cells in Confocal Imagesbased on Nuclear Protein Distribution Analysis

Background: The distribution of the chromatin-associatedproteins plays a key role in directing nuclear function. Previously, wedeveloped an image-based method to quantify the nuclear distributions ofproteins and showed that these distributions depended on the phenotype ofhuman mammary epithelial cells. Here we describe a method that creates ahierarchical tree of the given cell phenotypes and calculates thestatistical significance between them, based on the clustering analysisof nuclear protein distributions. Results: Nuclear distributions ofnuclear mitotic apparatus protein were previously obtained fornon-neoplastic S1 and malignant T4-2 human mammary epithelial cellscultured for up to 12 days. Cell phenotype was defined as S1 or T4-2 andthe number of days in cultured. A probabilistic ensemble approach wasused to define a set of consensus clusters from the results of multipletraditional cluster analysis techniques applied to the nucleardistribution data. Cluster histograms were constructed to show how cellsin any one phenotype were distributed across the consensus clusters.Grouping various phenotypes allowed us to build phenotype trees andcalculate the statistical difference between each group. The resultsshowed that non-neoplastic S1 cells could be distinguished from malignantT4-2 cells with 94.19 percent accuracy; that proliferating S1 cells couldbe distinguished from differentiated S1 cells with 92.86 percentaccuracy; and showed no significant difference between the variousphenotypes of T4-2 …
Date: September 5, 2006
Creator: Long, Fuhui; Peng, Hanchuan; Sudar, Damir; Levievre, Sophie A. & Knowles, David W.
System: The UNT Digital Library
Ultrafast Structural Rearrangements in the MLCT Excited State for Copper(I) bis-Phenanthrolines in Solution (open access)

Ultrafast Structural Rearrangements in the MLCT Excited State for Copper(I) bis-Phenanthrolines in Solution

Ultrafast excited state structural dynamics of [Cu{sup I}(dmp){sub 2}]{sup +} (dmp = 2,9-dimethyl-1,10-phenanthroline) have been studied to identify structural origins of transient spectroscopic changes during the photoinduced metal-to-ligand-charge-transfer (MLCT) transition that induces an electronic configuration change from Cu(I) (3d{sup 10}) to Cu(II) (3d{sup 9}). This study has important connections with the flattening of the Franck-Condon state tetrahedral geometry and the ligation of Cu(II)* with the solvent observed in the thermally equilibrated MLCT state by our previous laser-initiated time-resolved x-ray absorption spectroscopy (LITR-XAS) results. To better understand the structural photodynamics of Cu(I) complexes, we have studied both [Cu{sup I}(dmp){sub 2}]{sup +} and [Cu{sup I}(dpp){sub 2}]{sup +} (dpp = 2,9-diphenyl-1,10-phenanthroline) in solvents with different dielectric constants, viscosities and thermal diffusivities by transient absorption spectroscopy. The observed spectral dynamics suggest that a solvent-independent inner-sphere relaxation process is occurring despite the large amplitude motions due to the flattening of the tetrahedral coordinated geometry. The singlet fluorescence dynamics of photoexcited [Cu{sup I}(dmp){sub 2}]{sup +} were measured in the coordinating solvent acetonitrile, using the fluorescence upconversion method at different emission wavelengths. At the bluest emission wavelengths, a prompt fluorescence lifetime of 66 fs is attributed to the excited state deactivation processes due to the internal conversion …
Date: October 5, 2006
Creator: Shaw, G. B.; Grant, C. D.; Shirota, H.; Castner, E. W., Jr.; Meyer, G. J. & Chen, L. X.
System: The UNT Digital Library