Critical evaluation of the nonradiological environmental technical specifications. Volume 2. Surry Power Plants, Units 1 and 2 (open access)

Critical evaluation of the nonradiological environmental technical specifications. Volume 2. Surry Power Plants, Units 1 and 2

A comprehensive study of the data collected as part of the environmental Technical Specifications program for Units 1 and 2 of the Surry Nuclear Power Plant was carried out for the Office of Regulatory Research of the U.S. Nuclear Regulatory Commission. The program included an analysis of the hydrothermal and ecological monitoring data collected from 1973 through 1975. The hydrothermal analysis includes a discussion of models used in plume predictions prior to plant operation and an evaluation of the present hydrothermal monitoring program. The two primary methods used for temperature monitoring employ a fixed thermographs network and boat measurements. Review of data indicates that both the application and formulation of the hydrothermal monitoring program are inadequate to fully characterize the operation of the plant and the behavior of the thermal plume. Furthermore, there are no existing data that can be used to adequately verify or disprove the validity of the various Surry plume predictions. The ecological analysis includes validation of impacts predicted in the Final Environmental Statement using the operational monitoring data. Phytoplankton cell concentrations, chlorophyll a, and carbon-14 measurements were used to monitor changes in the primary producers. Densities of consumers (i.e., zooplankton, benthos, and fish) were sed to …
Date: August 10, 1976
Creator: Adams, S. M.; Cunningham, P. A.; Gray, D. D. & Kumar, K. D.
Object Type: Report
System: The UNT Digital Library
Review of electrostatic plugging (open access)

Review of electrostatic plugging

Using electric fields to diminish end losses from open magnetic plasma confinement systems is equivalent to magnetically shielding the grid wires of an electrostatic plasma confinement device. Electrostatically plugged magnetic cusps confine electrons magnetically in the perpendicular direction and electrostatically in the parallel direction, and ions are purely electrostatically confined in both directions. Theoretical estimates have been made of confinement times, electron density, plasma potential, and plasma temperatures. Experimentally, plasmas with n = 5 x 10/sup 12/ cm/sup -3/, T/sub i/ = 1 keV, tau = 5 msec, have been confined by cusp fields of about 10 kG with applied voltages approximately 10 kV. Fusion reactors with (fusion power)/(injection power) identical with Q approximately 5 appear feasible using B approximately 80 kG, applied voltage approximately 300 kV, if extrapolations from present experiments hold. Electrostatically plugged cusps are similar in some ways to Tandem Mirrors, to Tormac, and to SURMAC plasma confinement systems.
Date: August 10, 1977
Creator: Dolan, T. J.
Object Type: Report
System: The UNT Digital Library
Mirror reactor studies. [Design studies of fusion mirror, hybrid mirror, and two small mirror reactors] (open access)

Mirror reactor studies. [Design studies of fusion mirror, hybrid mirror, and two small mirror reactors]

Design studies of a fusion mirror reactor, a fusion-fission mirror reactor, and two small mirror reactors are summarized. The fusion reactor uses 150-keV neutral-beam injectors based on the acceleration of negative ions. The injectors provide over 1 GW of continuous power at an efficiency greater than 80 percent. The fusion reactor has three-stage, modularized, Venetian blind, plasma direct converter with a predicted efficiency of 59 percent and a new concept for removal of the lune-shaped blanket: a crane is brought between the two halves of the Yin-Yang magnet, which are separated by a float. The design has desirable features such as steady-state operation, minimal impurity problems, and low first-wall thermal stress. The major disadvantage is low Q resulting in high recirculating power and hence high cost of electrical power. However, the direct capital cost per unit of gross electrical power is reasonable ($1000/kW(e)).
Date: August 10, 1976
Creator: Moir, R. W.; Barr, W. L. & Bender, D. J.
Object Type: Report
System: The UNT Digital Library
DT fusion neutron irradiation of BNL--LASL superconductor wires (open access)

DT fusion neutron irradiation of BNL--LASL superconductor wires

The following samples were irradiated with the LLL rotating target neutron source: 19-core Nb/sub 3/Sn multifilament wires, Nb/sub 3/Sn single core, V/sub 3/Ga single core, NbTi Supercon 402, and NbTi cupronickel jacketed. No test results are given. (MOW)
Date: August 10, 1976
Creator: MacLean, S. C.
Object Type: Report
System: The UNT Digital Library
Feasibility of a MHD generator as a transmitter for electromagnetic sounding of the earth. [Mathematical models] (open access)

Feasibility of a MHD generator as a transmitter for electromagnetic sounding of the earth. [Mathematical models]

Development of a high-intensity source for use in time-domain electromagnetic (TDEM) soundings would permit investigation of geothermal systems to much greater depth than is now possible with controlled-source methods. The development of such a source is critically dependent upon a powerful, mobile generator. Magnetohydrodynamic pulse generators satisfy the weight and power requirements for such a generator. However, existing MHD generators which are used in geophysical applications are solid fueled, and therefore, very expensive to operate. Moreover, the pulse length from such a generator is limited to about 10 seconds, which may be too short to permit the maximum advantage to be gained from the available power. The shortcomings of the MHD generator will be remedied in a liquid-fueled generator now under development for the U.S. Air Force. A field program designed to compare available conventional and MHD generators would provide the necessary information for final generator selection, as well as an abundance of information on the nature of geothermal systems at depth. Operation and cost studies on MHD generators are given, and model calculations for TDEM soundings of geothermal hot-dry-rock systems are presented.
Date: August 10, 1976
Creator: Fleming, D. B.
Object Type: Report
System: The UNT Digital Library
Critical evaluation of the nonradiological environmental technical specifications. Volume 3. Peach Bottom Atomic Power Station Units 2 and 3 (open access)

Critical evaluation of the nonradiological environmental technical specifications. Volume 3. Peach Bottom Atomic Power Station Units 2 and 3

A comprehensive study of the data collected as part of the environmental Technical Specifications program for Units 2 and 3 of the Peach Bottom Nuclear Power Plant was conducted for the Office of Regulatory Research of the U.S. Nuclear Regulatory Commission. The program included an analysis of both the hydrothermal and ecological monitoring data collected from 1967 through 1976. Specific recommendations are made for improving both the present hydrothermal and ecological monitoring programs. Hydrothermal monitoring would be improved by more complete reporting of in-plant operating parameters. In addition, the present boat surveys could be discontinued, and monitoring efforts could be directed toward expanding the present thermograph network. Ecological monitoring programs were judged to be of high quality because standardized collection techniques, consistent reporting formats, and statistical analyses were performed on all of the data and were presented in an annual report. Sampling for all trophic groups was adequate for the purposes of assessing power plant induced perturbations. Considering the extensive period of preoperational data (six years) and operational data (three years) available for analysis, consideration could be given to reducing monitoring effort after data have been collected for a period when both units are operating at full capacity. In this …
Date: August 10, 1976
Creator: Adams, S. M.; Cunningham, P. A.; Gray, D. D.; Kumar, K. D. & Witten, A. J.
Object Type: Report
System: The UNT Digital Library
ORTAP: a nuclear steam supply system simulation for the dynamic analysis of high temperature gas cooled reactor transients (open access)

ORTAP: a nuclear steam supply system simulation for the dynamic analysis of high temperature gas cooled reactor transients

ORTAP was developed to predict the dynamic behavior of the high temperature gas cooled reactor (HTGR) Nuclear Steam Supply System for normal operational transients and postulated accident conditions. It was developed for the Nuclear Regulatory Commission (NRC) as an independent means of obtaining conservative predictions of the transient response of HTGRs over a wide range of conditions. The approach has been to build sufficient detail into the component models so that the coupling between the primary and secondary systems can be accurately represented and so that transients which cover a wide range of conditions can be simulated. System components which are modeled in ORTAP include the reactor core, a typical reheater and steam generator module, a typical helium circulator and circulator turbine and the turbine generator plant. The major plant control systems are also modeled. Normal operational transients which can be analyzed with ORTAP include reactor start-up and shutdown, normal and rapid load changes. Upset transients which can be analyzed with ORTAP include reactor trip, turbine trip and sudden reduction in feedwater flow. ORTAP has also been used to predict plant response to emergency or faulted conditions such as primary system depressurization, loss of primary coolant flow and uncontrolled removal …
Date: August 10, 1977
Creator: Cleveland, J. C.; Hedrick, R. A.; Ball, S. J. & Delene, J. G.
Object Type: Report
System: The UNT Digital Library
Critical evaluation of the nonradiological environmental technical specifications. Program description, summary, and recommendations. Vol. 1 (open access)

Critical evaluation of the nonradiological environmental technical specifications. Program description, summary, and recommendations. Vol. 1

A comprehensive study of the data collected as part of the environmental Technical Specifications program for eight nuclear power plants was conducted for the Office of Nuclear Regulatory Research of the U.S. Nuclear Regulatory commission. This report includes a summary of the screening phase in which the adequacy of the hydrothermal and ecological monitoring data for each plant were evaluated, and the summary and recommendations resulting from a detailed examination of the three nuclear power plants selected in the initial screening.
Date: August 10, 1976
Creator: Adams, S. M.; Cunningham, P. A.; Gray, D. D.; Kumar, K. D. & Witten, A. J.
Object Type: Report
System: The UNT Digital Library
Critical evaluation of the nonradiological environmental technical specifications. Volume 4. San Onofre Nuclear Generating Station, Unit 1 (open access)

Critical evaluation of the nonradiological environmental technical specifications. Volume 4. San Onofre Nuclear Generating Station, Unit 1

A comprehensive study of the data collected as part of the environmental Technical Specifications program for Unit 1 of the San Onofre Nuclear Generating Station (SONGS 1) was conducted for the Office of Nuclear Regulatory Research of the U.S. Nuclear Regulatory Commission. The program included an analysis of the hydrothermal and ecological monitoring data collected during 1975. The hydrothermal analysis includes a discussion of models used in plume predictions prior to plant operation and an evaluation of the present hydrothermal monitoring program. The ecological evaluation was directed toward reviewing the strengths and weaknesses of the various sampling programs designed to monitor the planktonic, benthic, and nektonic communities inhabiting the inshore coastal area in the vicinity of San Onofre.
Date: August 10, 1976
Creator: Adams, S. M.; Cunningham, P. A.; Gray, D. D. & Kumar, K. D.
Object Type: Report
System: The UNT Digital Library
Intra-undulator measurements at VISA FEL (open access)

Intra-undulator measurements at VISA FEL

We describe a diagnostics system developed, to measure exponential gain properties and the electron beam dynamics inside the strong focusing 4-m long undulator for the VISA (Visible to Infrared SASE Amplifier) FEL. The technical challenges included working inside the small undulator gap, optimizing the electron beam diagnostics in the high background environment of the spontaneous undulator radiation, multiplexing and transporting the photon beam. Initial results are discussed.
Date: August 10, 2000
Creator: Murokh, A.; Frigola, P.; Pellegrini, C.; Rosenzweig, J.; Tremaine, A.; Johnson, E. et al.
Object Type: Article
System: The UNT Digital Library
Liquid Phase Methanol LaPorte PDU: Modification, Operation, and Support Studies (open access)

Liquid Phase Methanol LaPorte PDU: Modification, Operation, and Support Studies

To strengthen the data base of the Liquid Phase Methanol LaPorte technology, research is being conducted in parallel with the process development unit engineering and construction efforts. This work will address alternate liquid media studies, effects of CO{sub 2} in CO-rich synthesis gas, optimization of in-situ catalyst reduction and storage, catalyst poison studies, fundamental kinetic modelling, testing alternate commercial catalysts, and field testing of new guard-bed materials for catalyst poisons. Tests will be performed primarily using CO-rich synthesis gas. (VC)
Date: August 10, 1988
Creator: Brown, D. M. & Frank, M. E.
Object Type: Report
System: The UNT Digital Library
Local Structure and Vibrational Properties of alpha-Pu, alpha-U, and the alpha-U Charge Density Wave (open access)

Local Structure and Vibrational Properties of alpha-Pu, alpha-U, and the alpha-U Charge Density Wave

The local atomic environment and vibrational properties of atoms in monoclinic pure {alpha}-plutonium as well as orthorhombic pure {alpha}-uranium and its low-temperature charge-density-wave (CDW) modulation are examined by extended x-ray absorption fine structure spectroscopy (EXAFS). Pu L{sub III}-edge and U L{sub III}-edge EXAFS data measured at low temperatures verify the crystal structures of {alpha}-U and {alpha}-Pu samples previously determined by x-ray diffraction and neutron scattering. Debye-Waller factors from temperature-dependent EXAFS measurements are fit with a correlated Debye model. The observed Pu-Pu bond correlated Debye temperature of {theta}{sub cD}({alpha}-Pu) = 162 {+-} 5 K for the pure {alpha}-Pu phase agrees with our previous measurement of the correlated Debye temperature of the gallium-containing {alpha}'-Pu phase in a mixed phase 1.9 at% Ga-doped {alpha}'-Pu/{delta}-Pu alloy. The temperature dependence of the U-U nearest neighbor Debye-Waller factor exhibits a sharp discontinuity in slope near T{sub CDW} = 43 K, the transition temperature at which the charge-density wave (CDW) in {alpha}-U condenses from a soft phonon mode along the (100) direction. Our measurement of the CDW using EXAFS is the first observation of the structure of the CDW in polycrystalline {alpha}-U. The different temperature dependence of the Debye-Waller factor for T < T{sub CDW} can be …
Date: August 10, 2004
Creator: Nelson, E J; Allen, P G; Blobaum, K M; Wall, M A & Booth, C H
Object Type: Article
System: The UNT Digital Library
LOTIS Upper Limits and the Prompt OT from GRB 990123 (open access)

LOTIS Upper Limits and the Prompt OT from GRB 990123

GRB 990123 established the existence of prompt optical emission from gamma-ray bursts (GRBs). The Livermore Optical Transient Imaging System (LOTIS) has been conducting a fully automated search for this kind of simultaneous low energy emission from GRBs since October 1996. Although LOTIS has obtained simultaneous, or near simultaneous, coverage of the error boxes obtained with BATSE, IPN, XTE, and BeppoSAX for several GRBs, image analysis resulted in only upper limits. The unique gamma-ray properties of GRB 990123, such as very large fluence (top 0.4%) and hard spectrum, complicate comparisons with more typical bursts. We scale and compare gamma-ray properties, and in some cases afterglow properties, from the best LOTIS events to those of GRB 990123 in an attempt to determine whether the prompt optical emission of this event is representative of all GRBs. Furthermore, using LOTIS upper limits in conjunction with the relativistic blast wave model, we weakly constrain the GRB and afterglow parameters such as density of the circumburster medium and bulk Lorentz factor of the ejecta.
Date: August 10, 2000
Creator: Williams, G. G.; Hartmann, D. H.; Park, H. S.; Porrata, R. A.; Ables, E.; Bionta, R. et al.
Object Type: Article
System: The UNT Digital Library
Spatially Resolved Spectra From a New X-Ray Imaging Crystal Spectrometer for Measurements of Ion and Electron Temperature Profiles (open access)

Spatially Resolved Spectra From a New X-Ray Imaging Crystal Spectrometer for Measurements of Ion and Electron Temperature Profiles

A new type of high-resolution X-ray imaging crystal spectrometer is being developed to measure ion and electron temperature profiles in tokamak plasmas. The instrument is particularly valuable for diagnosing plasmas with purely Ohmic heating and rf heating, since it does not require the injection of a neutral beam - although it can also be used for the diagnosis of neutral-beam heated plasmas. The spectrometer consists of a spherically bent quartz crystal and a two-dimensional position-sensitive detector. It records spectra of helium-like argon (or krypton) from multiple sightlines through the plasma and projects a de-magnified image of a large plasma cross-section onto the detector. The spatial resolution in the plasma is solely determined by the height of the crystal, its radius of curvature, and the Bragg angle. This new X-ray imaging crystal spectrometer may also be of interest for the diagnosis of ion temperature profiles in future large tokamaks, such as KSTAR and ITER, where the application of the presently used charge-exchange spectroscopy will be difficult, if the neutral beams do not penetrate to the plasma center. The paper presents the results from proof-of-principle experiments performed with a prototype instrument at Alcator C-Mod.
Date: August 10, 2004
Creator: Bitter, M.; HIll, K. W.; Stratton, B.; Roquemore, A. L.; Mastrovito, D.; Lee, S. G. et al.
Object Type: Article
System: The UNT Digital Library
A Comparison of Eight National Monuments as Applied to the Hanford Reach National Monument (open access)

A Comparison of Eight National Monuments as Applied to the Hanford Reach National Monument

On June 9, 2000, President William Clinton issued a proclamation to preserve 195,000 acres of land as a national monument in southeastern Washington State. Named the Hanford Reach Monument, it is managed by the U.S. Fish and Wildlife Service. The monument has been preserved by unusual circumstances: for the past 50 years, it has served as the buffer area to one of the U.S. Department of Energy's nuclear reservations. As such, it has been allowed to remain wild, protecting it from human interference and preserving a number of important resources once found in abundance, but now in decline, throughout the Columbia River Basin. At the centerpiece of this monument is the last free flowing, non-tidal stretch of the Columbia River. Called the Hanford Reach, this 51-mile long section of the Columbia River supports one of the most productive spawning grounds for Chinook salmon. In addition to its natural resources, this monument also contains sites of rich and important archaeological and historical significance. The U.S. Fish and Wildlife Service is currently working with the U.S. Department of Energy, the public, and a number of other interested parties to create a monument management plan, which is expected to be released sometime in …
Date: August 10, 2004
Creator: Pospical, Jill J.
Object Type: Report
System: The UNT Digital Library
Brightness Optimization of Ultra-Fast Thomson Scattering X-ray Sources (open access)

Brightness Optimization of Ultra-Fast Thomson Scattering X-ray Sources

We present simple scaling relations of the brightness a Thomson x-ray source on the electron and laser beam parameters in the case of a head (180 degree) interaction geometry. In particular, it is shown that a direct relation exists between the x-ray brightness and the electron beam brightness. These relations are discussed in the context of the PLEIADES Thomson x-ray source, where 10{sup 7} photons per pulse, with photon energies as high as 140 keV, have been produced by colliding a 0.25 nC, picosecond electron bunch with a 500 mJ, 50 fs, 800 nm laser pulse. The estimated peak brightness of the source is about 10{sup 16} photons/s/mm{sup 2}/mrad{sup 2}/0.1%b.w. A comparison of the current performance of the source and the predicted performance using optimized parameters is presented.
Date: August 10, 2004
Creator: Brown, W J & Hartemann, F V
Object Type: Article
System: The UNT Digital Library
A Visual Language for Data Mapping (open access)

A Visual Language for Data Mapping

I discuss a visual programming language and environment for doing data mapping between textual data files. Our experience using the environment is documented, as well as many of the constructs we used in the environment. I relate problems and solutions, and pose some questions to the readers of this document and the workshop.
Date: August 10, 2001
Creator: Carlson, J
Object Type: Article
System: The UNT Digital Library
Self-Organization Observed in Numerical Simulations of a Hard-Core Diffuse Z Pinch (open access)

Self-Organization Observed in Numerical Simulations of a Hard-Core Diffuse Z Pinch

None
Date: August 10, 2004
Creator: Makhin, V.; Siemon, R. E.; Bauer, B. S.; Esaulov, A.; Lindemuth, I. R.; Ryutov, D. D. et al.
Object Type: Article
System: The UNT Digital Library
Super-lotis early time optical counterpart measurements (open access)

Super-lotis early time optical counterpart measurements

We present an update on our ongoing effort to establish a dedicated observation program with an automated 0.6 meter telescope system that can detect GRB optical signals from 30 s to many hours after the start of the burst. The Super-LOTIS telescope has a 0.8 x 0.8{sup o} field-of-view, is sensitive to V 17 {approx} 19 objects, depending on the integration times, and will be placed at the Kitt Peak National Observatory. This paper presents technical aspects of this telescope and first results from initial operations at LLNL. Utilizing real-time coordinates from BATSE, BeppoSAX, XTE, IPN, HETE-2 and INTEGRAL, our LOTIS and SLOTIS systems will measure prompt GRB optical light curves that will enhance our understanding of GRBs.
Date: August 10, 2000
Creator: Park, H. S.; Porrata, R. A.; Williams, G. G.; Ables, E.; Band, D. L.; Barthelmy, S. D. et al.
Object Type: Article
System: The UNT Digital Library
Effect of Backscattered Electrons on Electron Beam Focus (open access)

Effect of Backscattered Electrons on Electron Beam Focus

Using an induction linac, ETA-II, we are studying the interaction of a 2 kA, 6 MeV electron beam focused to a <2 mm diameter spot on high-Z foils. A focus shift was noticed when changing from 5 mil to 40 mil tantalum foil targets. This shift was subsequently attributed to the effect of a substantial fraction of the incident electron beam backscattering from the target, reducing the net beam current. This fraction varies with the thickness and density of the target. The presence and magnitude of the backscattered component was confirmed using Faraday cup collectors and beam current monitors. Calculations confirm the magnitude of the focus shift is consistent with the observed backscattered fraction.
Date: August 10, 2000
Creator: Falabella, S.; Chen, Y. J.; Houck, T.; McCarrick, J.; Sampayan, S. & Weir, J.
Object Type: Article
System: The UNT Digital Library
Velocimetry Using Heterodyne Techniques (open access)

Velocimetry Using Heterodyne Techniques

At LLNL, we have been using heterodyne techniques for the past year and a half to measure velocities up to several kilometers-per-second on different types of experiments. We assembled this diagnostic, which we call the Heterodyne Velocimeter (HetV), using commercially available products developed for the communications industry. We use a 1550 nm fiber laser and single mode fibers to deliver light to and from the target. The return Doppler-shifted light is mixed with the original laser light to generate a beat frequency proportional to the velocity. At a velocity of 1000 m/s, the beat signal has a frequency of 1.29 GHz. We record the beat signals directly onto fast digitizers. The maximum velocity is limited by the bandwidth of the electronics and the sampling rate of the digitizers. The record length is limited by the amount of memory contained in the digitizers. This paper describes our approach to measuring velocities with this technique and presents recent data obtained with the HetV.
Date: August 10, 2004
Creator: Strand, O T; Berzins, L V; Goosman, D R; Kuhlow, W W; Sargis, P D & Whitworth, T L
Object Type: Article
System: The UNT Digital Library
Dipole septum magnet in the fast kicker system for multi-axis advanced radiography (open access)

Dipole septum magnet in the fast kicker system for multi-axis advanced radiography

Here we present designs for a static septum magnet with two adjacent apertures where ideally one aperture has a uniform dipole field and the other zero field. Two designs are considered. One is a true septum magnet with a thin layer of coils and materials separating the dipole field region from the null field region. During the beam switching process, the intense electron beam will spray across this material septum leading to concerns on beam control, vacuum quality, radiation damage, etc. due to the lost particles. Therefore, another configuration without a material septum is also considered. With this configuration it is more difficult to achieve high field quality near the transition region. Shaped shims are designed to limit the degradation of beam quality (emittance growth). Simulations are performed to obtain the magnetic field profile in both designs. A PIC simulation is used to transport a beam slice consisting of several thousand particles through the magnet to estimate emittance growth in the magnet due to the field non-uniformity.
Date: August 10, 2000
Creator: Wang, L.; Lund, S. M. & Poole, B. R.
Object Type: Article
System: The UNT Digital Library
Direct electrochemical conversion of carbon: systems for efficient conversion of fossil fuels to electricity (open access)

Direct electrochemical conversion of carbon: systems for efficient conversion of fossil fuels to electricity

The direct electrochemical conversion of carbon involves discharge of suspensions of reactive carbon particles in a molten salt electrolyte against an oxygen (air) cathode. (Figure 1). The free energy and the enthalpy of the oxidation reaction are nearly identical. This allows theoretical efficiencies ({Delta}G(T)/{Delta}H) to approach 100% at temperatures from 500 to 800 C. Entropy heat losses are therefore negligible. The activities of the elemental carbon and of the carbon dioxide product are uniform throughout the fuel cell and constant over discharge time. This stabilizes cell EMF and allows full utilization of the carbon fuel in a single pass. Finally, the energy cost for pyrolysis of hydrocarbons is generally very low compared with that of steam reforming or water gas reactions. Direct electrochemical conversion of carbon might be compared with molten carbonate fuel cell using carbon rather than hydrogen. However, there are important differences. There is no hydrogen involved (except from trace water contamination). The mixture of molten carbonate and carbon is not highly flammable. The carbon is introduced in as a particulate, rather than as a high volume flow of hydrogen. At the relatively low rates of discharge (about 1 kA/m{sup 2}), the stoichiometric requirements for carbon dioxide by …
Date: August 10, 2000
Creator: Cooper, J F; Cherepy, N & Krueger, R
Object Type: Article
System: The UNT Digital Library
Interaction Of Water Molecules With SiC(001) Surfaces (open access)

Interaction Of Water Molecules With SiC(001) Surfaces

We have investigated the interaction of water molecules with the polar Si- and C- terminated surfaces of cubic Silicon Carbide by means of ab initio molecular dynamics simulations at finite temperature. Different water coverages were considered, from {1/4} to a complete monolayer. Irrespective of coverage, we find that water dissociates on the silicon terminated surfaces, leading to important changes in both its structural and electronic properties. On the contrary, the carbon terminated surface remains inert when exposed to water. We propose experiments to reveal the ionic and electronic structure of wet Si-terminated surfaces predicted by our calculations, which at full coverage are notably different from those of hydrated Si(001) substrates. Finally, we discuss the implications of our results for SiC surface functionalization.
Date: August 10, 2004
Creator: Cicero, G; Catellani, A & Galli, G
Object Type: Article
System: The UNT Digital Library