The GaAs(100) surface is modeled by using atomic clusters in order to study the effects of passivation with sulfur. Both the Ga- and the As-terminated surfaces are tied off with S atoms in a 2 {times} 1 reconstruction. The most stable structure is established on the basis of ab initio Hartree-Fock calculations. It is found that after ...
Energy Citations Database
Research completed during the period 1 Feb. 1990 - 28 Feb. 1994 is summarized in the following included papers: 'Ab Initio Statistical Mechanics of Structural Phase Transition'; 'Ab Initio Molecular Dynamics: Analytically Continued Energy Functionals and Insights into Iterative Solutions'; 'Ab ...
NASA Astrophysics Data System (ADS)
Some of the concepts and theoretical techniques employed in recent ab initio studies of the electronic and structural properties of surfaces and interfaces are discussed. Results of total energy calculations for the 2 x 1 reconstructed diamond (111) surface and for stacking faults in Si are reviewed. 30 refs., 8 figs.
DOE Information Bridge
Some of the concepts and theoretical techniques employed in recent ab initio studies of the electronic and structural properties of surfaces and interfaces are discussed. Results of total energy calculations for the 2 x 1 reconstructed diamond (111) surfa...
National Technical Information Service (NTIS)
We present a combined experimental and theoretical study on carbon nanodiamonds using Raman and DAC experimentation and ab initio calculations. Our calculations confirm the surface reconstruction to a fullerene-like structure, and indicate compression of ...
We present a combined experimental and theoretical study on carbon nanodiamonds (NDs) using Raman and DAC experimentation and ab initio calculations. Our calculations confirm the surface reconstruction to a fullerene-like structure, and indicate compressi...
We discuss a recent investigation of adatom behavior on the AISb(001) surface using first-principles electronic structure methods based on the density functional theory. For Al and Sb adatoms, we find a number of novel adatom structures that differ dramat...
A new algorithm, MEDIC (Maximum Entropy Direct Inversion of Crystallographic Data), is presented that provides a direct method of inverting the observed integrated intensities in a diffraction experiment to yield the scattering density within a unit cell....
... This study involves: Ab-initio crystal orbitals and polymer orbitals; Ab-initio coupled cluster program; Ab-initio quantum chemical calculations and ...
DTIC Science & Technology
Structure determination of a novel macromolecular complex via single-particle electron microscopy depends upon overcoming the challenge of establishing a reliable 3-D reconstruction using only 2-D images. There are a variety of strategies that deal with this issue, but not all of them are readily accessible and straightforward to use. We have developed a "toolbox" of ...
PubMed
Structure determination of a novel macromolecular complex via single-particle electron microscopy depends upon overcoming the challenge of establishing a reliable 3-D reconstruction using only 2-D images. There are a variety of strategies that deal with this issue, but not all of them are readily accessible and straightforward to use. We have developed a �toolbox� of ...
PubMed Central
Ga- and As-terminated GaAs(100) surfaces are studied through first-principles density-functional pseudopotential calculations of the energies of surfaces with different stoichiometries and reconstructions. We predict structural transitions as a function of Ga and As chemical potentials within an experimentally accessible range which is shown to be fixed by the bulk energies of ...
Using a massively parallel computer, we undertake an ab initio investigation of the Si(111)-(7� 7) surface reconstruction. Calculation of the total energy of an �700 effective atom supercell at an 8 Ry plane wave cutoff allows us to determine (1) the energy difference between the (7� 7) and (2� 1) ...
... Title : Chalcopyrite Magnetic Semiconductors: An Ab-Initio Study of Their Structural, Electronic and Magnetic Properties. ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... COMPENDIUM OF AB INITIO CALCULATIONS ...
... Accession Number : ADA219907. Title : An Ab Initio Study of the Geometry and Rotational Barrier of 4- Phenylimidazole. ...
... from federally funded research, testing and training ... and agencies for Research Development Test and Evaluation ... Title : Ab Initio Calculations of the ...
... Title : Ab Initio Calculation of Vibrational Absorption and Circular Dichroism Spectra Using Density Functional Force Fields. ...
... Title : AB Initio Quantum Chemical Investigations of Solubilities in Supercritical Solutions. Descriptive Note : Conference Paper,. ...
An ab initio investigation of the Si(111)-(7�7) surface reconstruction is undertaken using the state of the art in massively parallel computation. Calculations of the total energy of an ~700 effective-atom supercell are performed to determine (1) the fully relaxed atomic geometry, (2) the scanning-tunneling-microscope images as a ...
A protocol to attain high-resolution single-particle reconstructions is presented. The protocol is the concatenation of two procedures: one to obtain an ab initio low-resolution reconstruction, the other to determine a fixed point of the consecutive applications of fast projection matching and 3D ...
... Title : AB Initio Study of the Electronic Magnetic Circular Dichroism ... functions are determined using as initio quantum chemical techniques including ...
We present the result of ab initio modeling of the Ge(111)-(2 � 1) surface electronic structure in the presence of donor doping atom at certain position in the surface bilayer of (2 � 1) reconstruction. We briefly compare these results with the data of experimental low temperature STM investigations. Ab ...
A novel density modification method is applied for the first time to phase reconstruction of x-ray single crystal data of quasicrystals. The structure of icosahedral Zn-Mg-Ho quasicrystals has been determined by means of this ab initio structure determination within a framework of a 6D description. The location, size, and shape of the ...
We report on the first experimental ab initio reconstruction of an image of a single particle from fluctuations in the scattering from an ensemble of copies, randomly oriented about an axis. The method is applicable to identical particles frozen in space or time (as by snapshot diffraction from an x-ray free electron laser). These ...
Due to recent advances in methods and computers, the accuracy of ab calculations has reached a point
NASA Technical Reports Server (NTRS)
Model-based, three-dimensional (3D) image reconstruction procedures require a starting model to initiate data analysis. We have designed an ab initio method, which we call the random model (RM) method, that automatically generates models to initiate structural analysis of icosahedral viruses imaged by cryo-electron microscopy. The ...
The reconstruction process of vacancy hole in carbon nanotube is investigated by tight-binding molecular dynamics simulations and by ab initio total energy calculations. In the molecular dynamics simulation, a vacancy hole is found to reconstruct into two separated pentagon-heptagon pair defects. As the result of ...
We comment on some new'' results concerning the energetics of W(100) reconstruction. They, in fact, reproduce our former results, obtained in a semiempirical tight-binding scheme, assuming from {ital ab} {ital initio} calculations a {ital d}-band filling of 4.4, which concluded in favor of a multilayer nature of ...
We have simulated with in the Density Functional Theory (DFT) spherically cut nano-diamonds from bulk diamond at ambient conditions. The 2.6 nanometer diameter sphere is then allowed to relax at 250K and surface reconstruction is observed. Four hemispherical fullerene like regions form on the surface and while the interior maintains the diamond structure, it undergoes ...
... AB-INITIO SIMULATION OF a/2110> ... 4. TITLE AND SUBTITLE AB-INITIO SIMULATION OF a/2110> SCREW DISLOCATIONS γ-TiAl 5c. ...
... ADP012740 TITLE: Ab Initio Study on Spin Polarization of III-V Compound Tips ... Ab initio study on spin polarization of III-V compound tips ...
Ab initio electronic structure methods can supplement CALPHAD in two major ways for subsequent applications to stability in complex alloys. The first one is rather immediate and concerns the direct input of ab initio energetics in CALPHAD databases. The o...
...with this part. The certificate shall be void ab initio for those vehicles causing the...issued, and the certificate may be deemed void ab initio. (C) The manufacturer...with this part. The certificate shall be void ab initio for those vehicles causing...
Code of Federal Regulations, 2010
... ADP023770. Title : ab-Initio Molecular Dynamics Simulations of Molten Ni-Based Superalloys. Descriptive Note : Conference paper. ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... of Molecular Modelling and Ab initio Molecular ...
... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : New AB Initio Based Density ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... Title : Development of Ab-initio Multibody ...
... Ab initio Energies Calculated Using 3 ... of the Transition States (TS ... Descriptors : *TRANSITIONS, *MOLECULES, COMPUTATIONS, COMPARISON ...
... Abstract : Results are presented from ab initio quantum chemical calculations on the ground state potential energy surface for the open shell ...
... from federally funded research, testing and training ... and agencies for Research Development Test and Evaluation ... Title : An Ab Initio Study of Solid ...
... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : An AB Initio Study of Dimethyl ...
... Accession Number : ADA523968. Title : Ab-initio Simulations of Molten Ni Alloys. Descriptive Note : Journal article (preprint). ...
... Title : Ab-Initio Molecular Dynamics Simulations of Molten Ni-Based Superalloys. Descriptive Note : Conference paper (preprint). ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... Title : Ab-Initio Molecular Dynamics Simulations ...
... We carried out ab-initio quantum chemical calculations on these energetic cyclic ethers and generated the electrostatic molecular potential contour ...
Ab initio quantum chemical techniques have been used to investigate weakly bund complexes of H20 and SO2. An energy gradient program was used to ...
NASA Website
... Accession Number : ADA351780. Title : Ab Initio and DFT Potential Energy Surfaces for Cyanuric Chloride Reactions. Descriptive Note : Final rept. ...
... Ab initio study on atomic structures and physical properties of CdSe quantum nanodots ... Figure 2. Diagram of covered nanodots. ...
... Title : Ab Initio Study on Atomic Structures and Physical Properties of CdSe Quantum Nanodots. Descriptive Note : Final rept. ...
... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : Ab Initio Study of the Structure ...
... Rydberg I 'Flu state. Demoulin and Jungen (1974) used an ab initio quantum chemical approach, but only at the SCF level ...
... moment has been cancelled a priori for the electronic transition as a function of R(CC), using ab initio quantum chemical techniques including state ...
... from federally funded research, testing and training ... and agencies for Research Development Test and Evaluation ... Title : Ab Initio Study of Ultracold ...
1 AB INITIO STUDIES ON HEXAVALENT PHOSPHORUS COMPOUNDS Ashley L. Wilson* Aberdeen High School Aberdeen, Maryland 21001 ...
... Accession Number : ADA436055. Title : Ab Initio Studies on Hexavalent Phosphorus Compounds. Descriptive Note : Conference paper. ...
... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : Ab Initio Relativistic Study of ...
... Accession Number : ADA440631. Title : Ab Initio Quantum Chemical Study of Electron Transfer in Carboranes. Descriptive Note : Journal article. ...
... Accession Number : ADA270577. Title : Ab Initio Potential Energy Surface for the H + OCS Reaction. Descriptive Note : Final rept. ...
... [2"- ARMY RESEARCH LABORATORY [C Ab Initio Potential Energy Surface for H + OCS Reactions: Extended Basis Sets ...
... Results of this study substantiate findings from an earlier quantum chemical study using a lower ... for (I) and (II) based on the earlier ab initio study. ...
... Ab initio direct trajectory simulation on hydrogen atom transfer in 7-azaindole in the electronic excited state with assist of water molecules ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... Title : Ab Initio Direct Trajectory Simulation on ...
... Title : Ab Initio Calculation of Vibrational Circular Dichroism Spectra Using Accurate Post-Self-Consistent-Field Force Fields: trans-2,3 ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... Title : Ab Initio Calculation of Intermolecular ...
... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : AB Initio Propagator Theory of ...
] as implemented in the Vienna ab initio simulation package (VASP) code [31,32] using a 3 3 1 k-point grid, plane methods. These were analyzed using electron direct methods (EDM 2.0.1) software [27] and in-plane atomic bonded to O1 (lower in energy than the alternative O2). Four calculations were performed using VASP: one
E-print Network
We have investigated the influence of a variety of dimer vacancy defects on the reactivity of F2 molecules with the clean Si(100)-2 x 1 reconstructed surface via molecular dynamics using an ab-initio-derived Stillinger-Weber-type many-body potential. Our ...
We report on the determination of a high quality ab initiu potential energy surface (PES) and dipole
RNA-Seq provides an unbiased way to study a transcriptome, including both coding and non-coding genes. To date, most RNA-Seq studies have critically depended on existing annotations, and thus focused on expression levels and variation in known transcripts. Here, we present Scripture, a method to reconstruct the transcriptome of a mammalian cell using only RNA-Seq reads and the ...
Dimer induced reconstruction and metallicity of Ge(001) surface has been studied using SIESTA. Using slab model, we modeled our surface starting with symmetric dimerization of the surface atoms, which on optimization goes over to asymmetric(buckled) dimerization. It is found that there is a substantial decrease in the total energy of the slab. Calculated PDOS for dimer atoms ...
We report orientation-specific, surface-sensitive structural characterization of colloidal CdSe nanorods with extended X-ray absorption fine structure spectroscopy and ab-initio density functional theory calculations. Our measurements of crystallographically-aligned CdSe nanorods show that they have reconstructed Cd-rich surfaces. They exhibit ...
This talk presents the result of an ab-initio study of Ruddlesden-Popper(RP) phases for Srn+1TinO3n+1(n = 1, 2, 3, ?) compounds with the density functional theory(DFT). In particular, we present results for the relation between octahedral rotations and external strains. We find that rotational reconstructions are energetically favorable under nonzero ...
Using X-ray diffraction Ghose et al. [S.K. Ghose, I.K. Robinson, P.A. Bennett, F.J. Himpsel, Surf. Sci. 581 (2005) 199] have recently produced a structural model for the quantum-wire surface Si(5 5 3) Au. This model presents two parallel gold wires located at the step edge. Thus, the structure and the gold coverage are quite different from previous proposals. We present here an ...
Two approaches for directly computing a molecular heat of formation based on sophisticated ab initio
An overview of the current understanding of ozone depletion chemistry, particularly with regards the
