We calculated the temperature dependence of the Debye-Waller factors for a variety of group IV, III-V and II-VI semiconductors from 0.1 to 1000 K. The approach used to fit the temperature dependence is described and resulting fit parameters are tabulated for each material. The Debye-Waller factors are deduced from generalized phonon densities of states which were derived from ...

ABINIT [http://www.abinit.org] allows one to study, from first-principles, systems made of electrons and nuclei (e.g. periodic solids, molecules, nanostructures, etc.), on the basis of Density-Functional Theory (DFT) and Many-Body Perturbation Theory. Beyond the computation of the total energy, charge density and electronic structure ...

-Bands �LM Suite �SEMC-2D �SETE �CPMD �EDIP �Silvaco �Cadence �Cats �TOMCAT �NWChem �ANEBA #12;ABINIT (www.abinit.org) First principles pseudo-potential code (plane wave basis) Model molecules, crystals, surfaces that takes advantage of ultra-soft pseudopotentials Transiesta-C � well ...

We study iron carbide, Fe3C, under pressure employing state-of-the-art first-principles calculations based on the planar-augmented wavefunctions (PAW) approach to density-functional theory (DFT) in the ABINIT implementation. We investigate in large detail the magnetism of the structure, considering a variety of spin configurations and ...

Expansion of the total energy of a crystal around a high-symmetry reference structure provides information about material properties including the phonon dispersion, responses to applied fields, magnetostructural coupling, and structural transitions. For complex oxides, parameterization of the structural energetics by real-space interatomic force constants (IFCs) provides a computationally ...

... By using Fourier coefficients of the periodic system as structural inputs, the present approach offers the advantage of circumventing the need for ...

The origin of the high piezoelectric response observed in complex solid solution perovskites like PbMg1/3Nb2/3O3-PbTiO3 (PMN-PT) is still not well understood. We have taken a multi-scale approach to examine PMN and PMN-PT by developing a shell potential model by fitting to extensive first-principles data that can then be used in molecular dynamics (MD) ...

- erties governing a material's phase stability. First-principles, computational- thermodynamic approaches in the first-principles computation of thermodynamic properties for disordered solids. The approach involves is based on the use of thermodynamic-integration methods to compute temperature-dependent free energies

... A pedigree summary metric is defined that characterizes the informational distance between individual fused products and source data. ...

We present results of a study from first principles modeling using ABINIT packages. Firstly, we would like to calculate the characteristic bulk properties of InAs and GaAs crystals and to use them in a kp model in order to study piezoelectricity in a truncated cone quantum dot. Secondly, we focused our attention on electronic ...

Alloy design could benefit greatly from a systematic approach that combines current empirical practices with the predictive capabilities of computer modeling such as first principles based methods. At this point in time, realization of such an aid to allo...

We present a hybrid approach for GW/Bethe-Salpeter Equation calculations of core excitation spectra including XAS, NRIXS and EELS. The method dubbed OCEAN, is based on 1) ab initio ground state wavefunctions from the plane-wave pseudopotential code ABINIT; 2) the NIST core-level Bethe-Salpeter Equation Lanczos solver; and 3) a many-pole GW self-energy ...

This paper presents the integral as a result of a theorem following from simple axioms. The approach is shown to be robust by further proving all of the usual theorems (and more) from these first principles.

We are studying complex perovskites Pb(Mn_1/3Nb_2/3)O3 (PMN) and PMN-PbTiO3 (PMN-PT) using frozen phonons, linear response, and molecular dynamics with a shell-model potential fitted to first-principles results. PMN is a relaxor with fascinating and controversial behavior, and is also the relaxor end member of the new high strain piezoelectric PMN-PT. For several ordered structures of PMN we have ...

Motivation EPC introduction A bit of theory Transport ABINIT Examples The electron-phonon coupling Quer�taro 1/67 #12;Motivation EPC introduction A bit of theory Transport ABINIT Examples Outline 1 Motivation 2-phonon coupling in ABINIT 5 April 2008 Quer�taro 2/67 #12;Motivation EPC introduction A bit of theory Transport

A weakness connected to the present interpretation of nuclear borehole logs is that the interdependence of the various logs and physical effects of importance for the tools are not always taken into account in a correct way. Therefore a new approach to th...

... A new approach based on "hybrid functionals" was used to overcome this problem I no main topics were pursued ( 11 Itchav ior of fluorine in nitride ...

... Traditional link analysis ideally supports Fusion Forms 5- 8. Table 1 leads to a number of important insights: 1. The first four fusion forms represent ...

We developed a relativistic dynamical mean field approach to study the properties of Plutonium Americium mixtures.

We present a hybrid approach for Bethe-Salpeter equation (BSE) calculations of core excitation spectra, including x-ray absorption (XAS), electron energy loss spectra (EELS), and nonresonant inelastic x-ray scattering (NRIXS). The method is based on ab initio wave functions from the plane-wave pseudopotential code abinit; atomic core-level states and ...

Nanostructures are presently enjoying an increasing interest in the field of materials science. In particular, importance is given to ordered monolayers prepared by deposition of atoms on a crystalline surface. The growth of these superlattices can be controlled so as to obtain an ordered structure by means of the lateral interaction of adatoms lying on the metal surface. The objective of our ...

Based on first principles supercell approach, we have successfully initiated and continued our study of defects in AlN, GaN, diluted nitrides and related wide gap materials. We have also investigated and implemented an approach to calculate the x-ray abso...

Catal. Lett. (accepted) First-Principles Approach to Heat and Mass Transfer Effects in Model-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany (Received August 21, 2009) We assess heat and mass transfer that integrates a detailed description of the surface reaction chemistry and the macro-scale flow structures

Magnetic structure of materials with defects presents a strong dependence on local atomic arrangements. This dependence affects mechanical, magneto-caloric, and magnetization properties. Insights into thermodynamic and magnetic fluctuations at defects in Fe are obtained from first principle analysis by deploying the first ...

We performed static first-principles calculations using the density functional theory as implemented in the ABINIT package to study the behavior of MgAl2O4 spinel, under pressure. We considered several possible structures for which we computed the enthalpy and the PV relations. The calculations showed that MgAl2O4 undergoes a phase transition sequence ...

We develop and apply an ab-initio approach to nuclear structure. Starting with the NN interaction, that fits two-body scattering and bound state data, and adding a theoretical NNN potential, we evaluate nuclear properties in a no-core approach. For presen...

ESTEST is a verification and validation (V&V) framework for electronic structure codes that supports Qbox, Quantum Espresso, ABINIT, the Exciting Code and plans support for many more. We discuss various approaches to the electronic structure V&V problem implemented in ESTEST, that are related to parsing, formats, data management, search, comparison ...

We have developed an approach, based on the LMTO-ASA formalism and the recursion method, which allow us to perform first principles spin-polarized self-consistent calculations of electronic structure in real space. To illustrate the method we obtain the e...

and the need to determine a dislocation core radius for each subinter- val over which the Read-Shockley formula in covalent materials from first principles over an entire misorientation range for given tilt axes #12;lations on selected grain boundaries usually short-period co- incident site structures in covalent

The diffusion of hydrogen is critical in the kinetics of hydrogen uptake and release in metal hydrides and in membrane-based approaches to hydrogen purification. First principles calculations have become a valuable counterpart to experimental methods to study hydrogen diffusion. Examples will be presented of using ...

Using the disordered local moment picture of itinerant magnetism, we present calculations of the temperature and volume dependence of the magnetic moment and spin-spin correlations for fcc Fe in the paramagnetic state. These calculations are based on the parameter-free, first principles approach of local spin density functional theory ...

A charge patching method and an idealized surface passivation are used to calculate the single electronic states of IV-IV, III-V, II-VI semiconductor quantum dots up to a thousand atoms. This approach scales linearly and has a 1000 fold speed-up compared to direct first principle methods with a cost of eigen energy error of about 20 ...

We report first-principles-based calculations, combined with an efficient Monte Carlo technique, that undoubtedly show that Pb(Zr0.5Ti0.5)O3, one of the most important ferroelectrics to date, adopts critical behavior that strongly deviates from the classical mean-field approach while being, in fact, consistent with the 3D-random Ising universality class. ...

The approach of surface splitting and Russian Roulette (RR) to variance reduction in fixed source Monte Carlo neutron and photon transport calculations is treated in a didactic fashion starting from first principles. The Direct Statistical Approach to opt...

The primary goal of the proposed research was to study and develop alloying concepts for understanding intermetallic alloys as derived from a first principles quantum mechanical approach. Thus, a major part of our effort was to study and determine ductili...

The Lagrangian approach to the two dimensional integrable systems (IS) is discussed. The Lagrangians proposed have the form of the interacting geometrical actions for the Kac-Moody and Virasoro groups. In one approach when the first principle is the gauge...

The conventional approach to treating charged defects in extended systems in first principles calculations is via the supercell approximation using a neutralizing jellium background charge. I explicitly demonstrate shortcomings of this standard approach a...

The objective of this research was to evaluate the applicability of theoretical approaches based on first principles to understand the ductility problem in intermetallic compounds. The predictive approach is based on all electron total energy band structu...

We have performed first-principles computation for the magnetic iron and iron-nickel over a wide range of pressure (0-400GPa) and temperature (0-6000K), within density-functional theory (DFT) in the generalized-gradient approximation using the projector augmented wave (PAW) method with the ABINIT code. We computed the free energies of hcp, bcc and fcc ...

We propose a dynamical mean-field approach for calculating the electronic structure of strongly correlated materials from first principles. The scheme combines the GW method with dynamical mean-field theory, which enables one to treat strong interaction effects. It avoids the conceptual problems inherent to conventional "LDA+DMFT," ...

We demonstrate an efficient and accurate first-principles method to calculate the electronic structure of a large system using a divide-and-conquer strategy based on localized quasi-atomic minimal basis set orbitals recently developed. Tight-binding Hamiltonian and overlap matrices of a large system can be constructed by extracting the matrix elements for a given pair of atoms ...

Language: English ...

The dissociative recombination (DR) of the AB(+) molecular ion with an electron has been shown to be an important component in the detailed interpretation of planetary ionosphere data. A first principles theoretical approach is developed for calculating t...

This paper describes a dynamic model that was developed to predict changes in turbine tip clearance the radial distance between the end of a turbine blade and the abradable tip seal. The clearance is estimated by using a first principles approach to model...

This paper develops the network theory of chemical reaction systems from first principles. The network approach is then used to derive a canonical set of differential equations for reaction--diffusion systems, and an analysis of the Brusselator is presented as an example. PMID:755597

Lattice gauge theory is our primary tool for the study of non- perturbative phenomena in hadronic physics. In addition to giving quantitative information on confinement, the approach is yielding first principles calculations of hadronic spectra and matrix...

and that further paleomagnetic studies also are crucial tests. The geologic tests outlined in Cowan et al. (1997 advocate an inclusive approach utilizing paleomagnetic, plate motion, paleontological, and geologic. Based on first principles, there are two means to determine a rock's original latitude. Paleomagnetism

The research on the fracture and fatigue crack-growth behavior of single crystal intermetallics was motivated by the need for improved high temperature engineering materials. The approach using a first principles total energy calculation of the energies o...

The paper summarizes work to date directed at defining a service- based functional decomposition of the fusion process. The resulting architecture accommodates (1) traditional sensor data, as well as human- generated input, (2) streaming and nonstreaming ...

A unified theory pertaining to the sensitivity of the propagation of an elastic wave to changes in the microstructural details of a material is discussed. In contrast to nearly all previous treatments a first principles approach, using developments from o...

An investigation is made as to whether one can derive, from first principles, simple scaling laws for complicated plasma devices such as a tokamak. The approach uses phenomenological transport coefficients to describe the anomalous transport. (MOW)

In an effort to develop efficient O(N) first-principles calculation algorithms, we devised the approach using wavelets as basis functions of electronic structure calculation. The theory of wavelets allows one to apply a multi-scale (multiresolution) analy...

A new approach for surface studies using the density functional formalism for structural determination and a first principles many-body theory for the quasiparticle surface state energies is discussed. The many-body calculation involves the evaluation of ...

Conventional methods to calculate the thermodynamics of crystals evaluate the harmonic phonon spectra and therefore do not work in frequent and important situations where the crystal structure is unstable in the harmonic approximation, such as the body-centered cubic (bcc) crystal structure when it appears as a high-temperature phase of many metals. A method for calculating temperature dependent ...

We present a first principles method for calculating positron lifetimes in solids, based on self-consistent calculations using the Linear Muffin-Tin Orbital method. Local density approximations are used for both electron-electron and electron-positron interactions. Results are presented for a variety of elemental metals and vacancies to demonstrate the ...

In this paper, from first-principles, we obtained the thermodynamically complete EOS for hematite for pressures up to 50GPa and temperatures up to 1000K. In the framework of DFT, we implemented the ground state calculations using sGGA and projector augmented wave approach. Particularly, the Hubbard-U method is used to describe the on-site Coulomb ...

A Car-Parrinello-type first-principles molecular-dynamics approach capable of treating the partial occupancy of electronic states that occurs at the Fermi level in a metal is presented. The algorithms used to study metals are both simple and computationally efficient. We also discuss the connection between ordinary electronic-structure calculations and ...

The authors present a first principles based semiclassical model for transport in an inhomogeneous magnetic layered structure. The approach solves the Boltzmann transport equation using the band structure, Bloch wave velocities and scattering matrices, describing the reflection and transmission of Bloch waves from interfaces, derived ...

First-principles calculations of formation energies for 243 different configurations of the Cr-Ni-Re ? phase were used to calculate a ternary phase diagram in the Bragg-Williams-Gorsky approximation (BWG) and to model finite-temperature thermodynamic properties. The binary and ternary phase diagrams were then calculated at different temperatures. Correct topology of the ...

First-principles-based Monte Carlo approaches are developed to investigate finite-temperature properties of stress-free nanodots made of the ferroelectric Pb(Zr,Ti)O3 system and of the multiferroic BiFeO3 compound. These zero-dimensional materials both exhibit various, novel chiral patterns for the tilting of the oxygen octahedra. Such exotic patterns ...

The electronic structure and transport properties of silver (Ag) and copper (Cu) nanowires of diameters up to 1.7 nm are investigated using first principles density functional theory and the Landauer formalism in conjunction with a supercell approach. A direct comparison of the ballistic conductances, quantum capacitances, and kinetic ...

Among the phases of SiO2 are alpha and beta cristobalite. Despite early indications that the higher-temperature beta phase might be cubic (Fd3m), it is now accepted that it is in fact tetragonal (I42d), and that the experiments suggesting a cubic structure were averaging spatially or dynamically over tetragonal domains. Recently, Zhang and Scott (J. Phys. Cond.Matt. 19, 275201) suggested that the ...

We report first principles density functional studies using plane wave basis sets and pseudopotentials and all-electron linear augmented plane wave (LAPW) of the relative stability of various ferroelectric and antiferroelectric supercells of PMN (PbMg1/3Nb2/3O3) for 1:2 chemical ordering along [111] and [001]. We used linear response with density ...

In our quest for accurate linear scaling first-principles molecular dynamics methods for pseudopotential DFT calculations, we investigate the accuracy of real-space grid approaches, with finite differences and spherical localization regions. We examine how the positions of the localization centers affect the accuracy and the convergence rate of the ...

The conventional approach to treating charged defects in extended systems in first principles calculations is via the supercell approximation using a neutralizing jellium background charge. I explicitly demonstrate shortcomings of this standard approach and discuss the consequences. Errors in the electrostatic ...

Semiempirical interatomic potentials are developed for silicon and carbon by modeling the total energy of the system using tight-binding approaches. The parameters of the models were obtained by fitting to results from accurate first-principles Local Dens...

Some theoretical approaches are reviewed to analyze crystallographic and optical properties of phosphors for white light emitting diodes. Stresses are placed on 1) local electro-neutrality for the structural stability of hosts, and 2) dielectric property and coordination of anion ligands around rare-earth luminescent centre for the tuning of emission colour. ...

We present an {ital ab} {ital initio} approach for the computation of the magnetic susceptibility {chi} of insulators. The approach is applied to compute {chi} in diamond and in solid neon using density functional theory in the local density approximation, obtaining good agreement with experimental data. In solid neon, we predict an observable dependence ...

Parameter-free electronic structure approaches are now being used to predict chemical order, and to a lesser extent, structural transformations in multi-component alloys, as a function of temperature, concentration and pressure. The underlying state-of-the-art framework will be briefly reviewed, and applications to specific aspects of the statics and kinetics of alloy ...

reaction chemistry must then be complemented by an appropriate treatment of the macroscopic heat and massFirst-Principles Approach to Heat and Mass Transfer Effects in Model Catalyst Studies Sebastian We assess heat and mass transfer limitations in in situ studies of model catalysts with a first

calculations can provide fundamental insights at the level not achievable through experiments alone. Here we (SIC-LSD) approximation [3] used in the current work is an approach which improves on the LSD treatment of correlations by removing an unphysical electron self-interaction inherent in the LSD. The SIC-LSD approach

The computation of electronic structure, total energy, forces and many related properties of condensed matter, thanks to density-functional theory (DFT), is a field in constant progress. A DFT software project that wants to stay at the frontier of knowledge cannot be the work of a single individual, neither of a small group. Also, up-to-date software engineering concepts can considerably ease the ...

The Gibbs energy function of Sr(6)Co(5)O(15) is calculated by first-principles for use in CALPHAD thermodynamic modeling. An efficient method is employed, using the Debye-Gru?neisen model to predict the temperature dependence of the heat capacity and entropy. The equation of state from first-principles and the Debye temperature from harmonic phonon calculations by the ...

The orientational dependence of charge-carrier mobilities in organic semiconductor crystals and the correlation with the crystal structure are investigated by means of quantum chemical first-principles calculations combined with a model using hopping rates from Marcus theory. A master equation approach is presented which is numerically more efficient than ...

A method to calculate NMR J-coupling constants from first principles in extended systems is presented. It is based on density functional theory and is formulated within a planewave-pseudopotential framework. The all-electron properties are recovered using the projector augmented wave approach. The method is validated by comparison with ...

First-principles quasi-harmonic calculations play a fundamental role in mineral physics because they can predict the structure and thermodynamic properties of materials at pressure and temperature conditions that are still challenging for experiments. They also enable calculations of thermal elastic properties by providing the second derivatives of the free energies with ...

As the first step in investigating the selective area chemical vapor deposition of titanium compounds, which are of considerable interests in semiconductor technology, a thermodynamic analysis has been performed for the selective area chemical vapor deposition of titanium nitride, over an extensive temperature, pressure, and composition range, using the alternating cyclic (A.C.) process. In this ...

Language: English ...

Language: English ...

... Accession Number : ADD809369. Title : First Principles of Concurrent Engineering: A Competitive Strategy for Electronic Product Development. ...

... 2005 4. TITLE AND SUBTITLE First Principles and Multiscale Modeling of Spallation and Erosion of Gun Tubes 5. FUNDING ...

... Title : First Principles Theory of the Interaction of Hydrogen with Surfaces and Bulk of Transition Metals. Descriptive Note : Annual rept. ...

... Title : First Principles Pseudopotential Calculations of Electronic and Atomic Properties of Solid and Liquid Alkali Metals. ...

... Title : First Principles Calculations on the Diffusion of Cu, Ag and Au Atoms or Aggregates on the Bulk and Surface of Titania. ...

... unlimited. First Principles Calculations of the Adsorption of Nitromethane ... most stable adsorption configurations parallel to the surface. ...

... Accession Number : ADA542606. Title : First Principles Calculation of Stress Induced Amorphization in Armor Ceramics. ...

... Accession Number : ADA544982. Title : Acquisition Improvement Challenges: First Principles. Descriptive Note : Briefing charts. ...

We develop and apply an ab-initio approach to nuclear structure. Starting with the NN interaction, that fits two-body scattering and bound state data, and adding a theoretical NNN potential, we evaluate nuclear properties in a no-core approach. For presently feasible no-core model spaces, we evaluate an effective Hamiltonian in a cluster ...

The adhesion of plastics to ceramics is important for many industrial and technological appliations. It is therefore essential to understand the underlying structure and bonding of the polymer and the surface. The aim of this research is to improve plastic adhesion using a multiscale approach. The first step involves the use of density functional calculations to understand the ...

In performing assessments of low probability, high consequence systems, it is often preferable to use more than one methodology in order to assure that such systems undergo a thorough assessment. Hence, employing two methodologies in a complementary manner allows the analyst to bring the strongest features of each approach to bear upon the problem. The results of one ...

The structural and vibrational properties of amorphous germanium oxide (a-GeO2) are investigated using first-principles calculations based on density functional theory. We first generate an a-GeO2 structure by first-principles molecular dynamics and analyze its structural properties. The vibrational spectra is then calculated within a density-functional ...

We investigate the functionalization of functional groups to graphene nanoribbons with zigzag and armchair edges using first-principles calculations. We find that the formation energy for the configuration of the functional groups functionalized to the zigzag edge is ~0.2 eV per functional group lower than that to the armchair edge. The formation energy difference arises from ...

We present a first principles method for calculating positron lifetimes in solids, based on self-consistent calculations using the Linear Muffin-Tin Orbital method. Local density approximations are used for both electron-electron and electron-positron interactions. Results are presented for a variety of elemental metals and vacancies to demonstrate the ...

In a system at non-uniform temperature some of the heat which flows from hotter regions to colder ones can produce nonthermal energy quite apart from whether or not the system undergoes changes in its state. A general mathematical formulation of the first principle of thermodynamics is given which explicitly takes into account the nonthermal energy ...

We present first-principles, density-functional theory calculations of the NMR chemical shifts for polycyclic aromatic hydrocarbons, starting with benzene and increasing sizes up to the one- and two-dimensional infinite limits of graphene ribbons and sheets. Our calculations are performed using a combination of the recently developed theory of orbital magnetization in solids, ...

We present first-principles and molecular dynamics studies for humidity dependence of optical property of a deoxyribonucleic acid (DNA) double helix fiber. The first-principles electronic structure and the molecular dynamics simulations reveal that the electronic structure of the DNA fiber is varied by the hydration amount or the relative humidity. We show that the ultraviolet ...

First-principles theoretical investigations of the noncollinearity of atomic spin moments in manganese clusters have been carried out within a gradient-corrected density-functional approach. Our studies on Mn5 and Mn6 include investigation of both collinear and noncollinear arrangements. It is shown that while the atomic structure of the ground state of ...

Using a recently developed first-principles approach, we show that the variation in the superconducting behavior of group IVb and Vb transition metal carbides is associated with a significant nesting of the Fermi surfaces in group Vb compounds, while their phonon anomalies and density of states at the Fermi level play a minor role. The superconducting ...

We present the results of our first-principles relativistic calculations of the fine-structure intervals and magnetic dipole transition probabilities for the 1{ital s}{sup 2}2{ital p} configuration of the lithium isoelectronic sequence using a variational approach. The contributions of the Breit interaction and approximate Lamb-shift corrections are ...

We present a generalized approach for computing electron conductance and I-V characteristics in multiterminal junctions from first-principles. Within the framework of Keldysh theory, electron transmission is evaluated employing an O(N) method for electronic-structure calculations. The nonequilibrium Green function for the nonequilibrium electron density of ...

Heisenberg exchange parameters at the interface of antiferromagnetic NiMn with ferromagnetic Co are calculated from first-principles. The authors use a layer version of the Korringa-Kohn-Rostocker multiple scattering approach and an expression, which is based on the expansion of the band energy, to calculate the exchange parameters from the underlying ...

First-principles calculation of the transverse conductance across DNA fragments placed between gold nanoelectrodes reveals that such conductance describes electron tunneling that depends critically on geometrical rather than electronic-structure properties. By factoring the first-principles result into two simple and approximately independent tunneling factors, we show that ...

Recent advances in computational techniques have led to the possibility of performing first principles calculations of the energetics of alloy formation on systems involving several hundred atoms. This includes impurity concentrations in the 1% range as well as realistic models of disordered materials (including liquids), vacancies, and grain boundaries. ...

We propose that the ideal fracture energy of a material with mobile bulk impurities can be obtained within the framework of a Born-Haber thermodynamic cycle. We show that such a definition has the advantage of initial and final states at equilibrium, connected by well-defined and measurable energetic quantities, which can also be calculated from first ...

We present first-principles calculations of x-ray absorption spectra of graphene and hexagonal BN monolayer on the Ni(111) substrate. Including dynamical core-hole screening effects according to the theory of Mahan-Nozi�res-de Dominics (MND) results in an overall good agreement with previously published experimental data and our new observations. This ...

We present our first-principles investigation of the influence of dispersion forces (or van der Waals interactions) on the self-assembly of styrene nanowires on the hydrogenated Si(100) 2x1 surface. Using density functional theory (DFT) calculations and kinetic Monte Carlo (KMC) simulations we demonstrate that the dispersion forces enhance the binding between styrene molecules ...

We report first principles analysis of the band gap Eg of ternary group-III nitride InxGa1-xN in both the wurtzite and zincblende form, within the linear muffin-tin orbital (LMTO) density functional theory method. We have implemented the semilocal modified Becke-Johnson (MBJ) exchange potential to accurately determine the band gap. The doping of In atoms ...

Electronic structure and phase stability properties of Ni-Ti and Ni-Al around equiatomic composition are investigated with a first principles approach. The study is based upon the generalized purturbation method applied to the Korringa-Kohn-Rostoker multiple scattering formulation of the coherent potential approximation. Within this ...

Contents Introduction 1 1 Motivation of the work 5 1.1 Lattice dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Molecular Dynamics and the Quasi Harmonic Approximation . . . . . . . . 7 1.3 Beryllium vs. Magnesium . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.4 Be(0001) surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2 ...

We investigated intermolecular interactions in weakly bonded molecular assemblies from first principles, by combining exact exchange energies (EXX) with correlation energies defined by the adiabatic connection fluctuation-dissipation theorem, within the random phase approximation (RPA). We considered three different types of molecular systems: the benzene ...

First-Principles Molecular Dynamics (FPMD) is an accurate, atomistic simulation approach that is routinely applied to a variety of areas including solid-state physics, chemistry, biochemistry and nanotechnology. FPMD enables one to perform predictive materials simulations, as no empirical or adjustable parameters are used to describe a given system. ...

The Yang-Mills theory lies at the heart of our understanding of elementary particle interactions. For the strong nuclear forces, we must understand this theory in the strong coupling regime. The primary technique for this is the lattice. While basically an ultraviolet regulator, the lattice avoids the use of a perturbative expansion. I discuss some of the historical circumstances that drove us to ...

The photon picture of radiation transport is examined. Because the photon has no mass and spin one, a position operator for a photon particle cannot be defined properly. This lack leads to ambiguity if the radiative transfer equation is associated with a quantum transport equation for photons. The issue of photon nonlocalizability is discussed and illustrated through a wavefunction-based ...

I discuss some of the historical circumstances that drove us to use the lattice as a non-perturbative regulator. This approach has had immense success, convincingly demonstrating quark confinement and obtaining crucial properties of the strong interactions from first principles. I wrap up with some challenges for the future.

The causal approach is used to model natural and man-made physical systems. Human beings tend to have a causal view of physical phenomena. A reasoning formalism based on the simultaneous use of the concept of causality and first principles is proposed. A ...

The scientific basis of nanotechnology as envisaged from the first principles is compared to bulk behavior. Development of nanoparticles having controllable physical and electronic properties has opened up possibility of designing artificial solids. Top down and bottom up approaches are emphasized. The role of nanoparticle (quantum ...

The London-Eyring-Polanyi-Sato (LEPS) model is a promising means for obtaining descriptions of hydrogen-metal interactions that are more realistic than those obtained via the assumption of purely pairwise interactions. This approach should be of particular value for the transition metals, for which first-principles pseudopotential methods cannot be used to ...

We present a general and systematic electronic structure theory of the nuclear magnetic resonance shielding tensor and the associated chemical shift for paramagnetic atoms, molecules, and nonmetallic solids. The approach is for the first time rigorous for an arbitrary spin state as well as arbitrary spatial symmetry and is formulated without reference to spin susceptibility. ...

Lattice gauge theory is our primary tool for the study of non- perturbative phenomena in hadronic physics. In addition to giving quantitative information on confinement, the approach is yielding first principles calculations of hadronic spectra and matrix elements. After years of confusion, there has been significant recent progress in ...

-8984(97)82806-8 An interatomic potential study of the properties of gallium nitride Peter Zapol, Ravindra Pandey and Julian D derived for gallium nitride within the shell- model approach. It was shown that the potential set in agreement with the results of recent first-principles calculations. 1. Introduction Gallium nitride has

-interaction-corrected local-spin-density SIC-LSD approximation is used to describe the electronic structure of dioxides REO2 configurations are in good agreement with experiment. Total energy considerations are exploited to show the link, a possible approach is to derive the intra-atomic Coulomb energy U from experiment, as was done in connection

Starting from TB-LMTO electronic structure total energy calculations of ordered binary alloys, we have determined the configurationally averaged effective (multisite) cluster interactions (ECI's) using the Connolly-Williams inversion method. The configura...

expansion of the free energy is truncated at a low order in the applied electric field, allowing-5112 online DOI: 10.1080/00150190490454855 First-Principles Theory of Polarization and Electric Fields approaches to the theoretical treatment of ferroelectrics and related materials in finite electric fields

We apply a new first principles approach for evaluating the spin dynamics for arbitrary magnetic systems. The method is implemented within the local density approximation and applied to {gamma}-Fe, a frustrated system where we obtain new low-energy magnetic configurations. {copyright} {ital 1996 American Institute of Physics.}

Precise first-principles spin-polarized total-energy and band-structure calculations have been performed for the zinc-blende Mn chalcogenides with the use of the local-spin-density (LSD) approach. We find that the LSD is capable of identifying the correct magnetic-ground-state structure, but it overestimates the ordering temperature [ital T][sub [ital N

We compute, from first principles, the dielectric function and electron energy loss spectrum (EELS) of an oxidized Si(100)(2�2) surface. The surface local field effect is found to be important for the calculation of EELS in a reflection geometry. Theoretical problems that arise when local fields are included within the periodic supercell ...

This paper describes our first-principles derivation of the Hamiltonian for the calculation of the bound states for a particle with a spatially varying mass in an arbitrary potential well. Our approach is based on the Feynman path-integral technique and results in a Hermitian form of the Schroedinger equation that conserves current at the boundary. We ...

The validity of using the Saha equation to describe the behavior of a two-temperature system is derived from first principles. The conditions for the validity of this approach are given. The analysis applies to the case of free carriers in a weakly ionized dense medium. In a multitemperature system the entropy is a more useful quantity ...

The prediction of structure at the atomic level is one of the most fundamental challenges in condensed matter science. Here we survey the current status of the field and consider recent developments in methodology, paying particular attention to approaches for surveying energy landscapes. We illustrate the current state of the art in this field with topical applications to ...

This book offers a new approach to understanding computer architecture, emphasizing the quantitative aspects of design and practical trade-offs that must be made. The authors establish the first principles of computer architecture through an examination of performance data and real-world machines. The book presents an understanding of ...

The confinement regime in SU(N) LGT is studied via approximate RG decimations that connect short to long distance scales. The decimations turn out to provide both upper and lower bounds on the exact partition function. By interpolation, this leads to a representation of the exact partition function in terms of successive decimations whose effective couplings flows are related to those of the ...

The specific interaction of biological molecules with one another is fundamental to the biochemistry of all living things. Equilibrium sedimentation is a classic method of biochemistry that provides first-principle thermodynamic information about the molar mass, association energy, association stoichiometry, and thermodynamic nonideality of molecules in solution. It is one of ...

In this paper we discuss methods to obtain high dopant concentrations during processing of Si devices. The possibility of increasing the solubility of B in Si by misfit stress is investigated. The enthalpy of B atoms is calculated, with and without stress, using density functional theory. A second approach, the trapping of excess dopant atoms during deposition of Si, is also ...

in steel metallurgy are stifled by the lack of thermodynamic data for the carbide phases, and as resulting by preventing cementite (Fe3C) precipitation using silicon as an alloying addition to the steel. The austeniteAbstract. The formation enthalpy of a series of Fe-C carbides has been estimated using a first

1 2 3 4 m G (GeV) FIGURE 1. The quenched LGT glueball spectrum of Morningstar and Peardon [1, 2 to these methods. In parallel, the "first principles" LGT approach [1, 5, 6] has made great progess in its applications to the spectrum of pure #12; glue and mixed quark�gluon states. In the glueball sector the LGT

The first-principles calculations of the lattice dynamics of the TlGaSe2 ternary semiconductor compound are presented in this paper. Calculations were performed using open-source code ABINIT on the basis of the density functional perturbation theory within the plane-wave pseudopotential approach. Results on the frequencies of phonon modes in the centre of ...

We propose a combined ab initio-spin quantum Monte Carlo (QMC) approach to compute thermodynamic properties of magnetic materials by first principles. The key to the proposed approach is a mapping of the magnetic long-range system onto an effective, nearest-neighbor quantum Heisenberg model, for which the QMC ...

An ab initio based approach to determine energies and structures for semicoherent interfaces is developed and applied to the Fe(001)/VN(001) system. To account for elastic displacements resulting from the lattice misfit, we compare an atomistic approach using a model potential (embedded-atom method) with a continuum approach using the ...

A synergistic approach that combines first-principles theory and electron photodetachment experiment is shown to be able to uniquely identify the ground state of a nearly degenerate cluster in the gas phase. Additionally, this approach can complement the Stern-Gerlach technique in determining the magnetic moment of small clusters ...

The U-Al binary system exhibits the formation of three intermetallic compounds: cubic Laves phase C15 UAl2, cubic L12 UAl3, and orthorhombic D1b UAl4. However, some uncertainties are found in the literature concerning UAl4 structure and composition. A computational first principles based approach is a useful tool to shed some light on ...

Electron transport in nanostructures is calculated and compared using a time-independent and a time-dependent first-principles framework. The time-independent approach uses the nonequilibrium Green�s-function technique to calculate the current, while the time-dependent method extracts the current from the time propagated wave function. The ...

The immense increase in the generation of genomic scale data poses an unmet analytical challenge, due to a lack of established methodology with the required flexibility and power. We propose a first principled approach to statistical analysis of sequence-level genomic information. We provide a growing collection of generic biological ...

Lattice simulation of supersymmetric gauge theories is not straightforward. In some cases the lack of manifest supersymmetry just necessitates cumbersome fine-tuning, but in the worse cases the chiral and/or Majorana nature of fermions makes it difficult to even formulate an appropriate lattice theory. We propose circumventing all these problems inherent in the lattice ...

We discuss the derivation and interpretation of a generalized surface phase diagram, based on first-principles density-functional calculations. Applying the approach to hydrogenated GaN surfaces, we find that the Gibbs free energies of relevant reconstructions strongly depend on temperature and pressure. Choosing chemical potentials as variables results in a phase diagram that ...

We report first-principle results for the electronic transport properties of silicon nanowires along the <110> direction with hydroxyl surface defects. The Hamiltonian and overlap matrices of the system are obtained using an all-electron, Gaussian-basis, local-density functional approach adapted for helical symmetry and the transport calculation ...

The conventional approach to treat charged defects in extended systems in first principles calculations is via the supercell approximation using a neutralizing jellium charge. I explicitly show that errors in the resulting electrostatic potential surface are comparable to a band gap energy in semiconductors, for cell sizes typically ...

The conventional approach to treat charged defects in extended systems in first principles calculations is via the supercell approximation using a neutralizing jellium charge. I explicitly show that errors in the resulting electrostatic potential surface are comparable to a band gap energy in semiconductors, for cell sizes typically ...

First-principles quasiharmonic calculations play a very important role in mineral physics because they can predict the structural and thermodynamic properties of materials at pressure and temperature conditions of the Earth's interior that are still challenging for experiments. They also enable calculations of thermal elastic properties by providing second-order derivatives of ...

Present theoretical and computational approaches, combined with the impressive advances in computer hardware and software, open the possibility for materials design from first principles. This article presents a perspective on the relevant developments in computational chemistry, solid state physics and statistical mechanics and it ...

... Accession Number : ADA147954. Title : Spark Column Plasma Dynamics Model (A First Principles Model for Laser Triggered Spark Gaps). ...

Using First-Principles Simulations. Accomplishments of this year are in four ...... [16] D. G. Crighton, Basic principles of aerodynamic noise generation, ...

to perform innovative design of mechanical structures from first principle knowledge. The method is based on the assumption that the crcorion of innovative ...

... Title : First-Principles Calculations of the Adsorption of Nitromethane and 1,1-Diamino-2,2-dinitroethylene (FOX-7) Molecules on the Al(111 ...

... Accession Number : ADA324581. Title : First-Principles Calculations for Ferroelectrics. Descriptive Note : Final rept. 1 Nov 93-31 Dec 96,. ...

... Accession Number : ADA331270. Title : First Principles: The Foundation of Twenty-First Century Army Operations. Descriptive Note : Final rept. ...

... Title : First Principles and Multi-Scale Modeling of the Roles of Impurities and Dopants on Thermal Barrier Coating Failure. ...

... First Principles Study of Soliton Hyperfine Interactions C: .NO0014-90-WX- 24264 ... Hyperfine Interactions, Solitons, Deep Levels, Semiconducting 4 ...

... Accession Number : ADD147095. Title : First Principles Study of Phase Stability in the Al-Ti System. Descriptive Note : Journal article,. ...

... Accession Number : ADD205039. Title : First Principles Study of Interfacial Adhesion: The Mo/MoSi2 Interface With and Without Impurities. ...

Sep 3, 2010 ... SUBTOPIC TITLE: Materials and Structures for Future Aircraft. PROPOSAL TITLE: First Principles Identification of New Aircraft Materials ...

... Title : First Principles Calculations of the Chemisorption Properties of Nitro-Containing Molecules on the Al2O3(0001) Surface. ...

... Title : First Principles Calculations of the Adsorption of Nitromethane and 1,1-Diamino-2,2-dinitroethylene (FOX-7) Molecules on Al2O3(0001 ...

... Accession Number : ADA339560. Title : First Principles Calculations Using Linear Response Theory for Ferroelectrics. Descriptive Note : Final rept. ...

... Accession Number : ADA300323. Title : First Principles Calculations Using Linear Response Theory for Ferroelectrics. Descriptive Note : Final rept. ...

Sep 18, 2007 ... When fully developed and validated, our first principles based formulation for the modeling of elastomeric devices will be available for ...

Oct 23, 2008 ... -All Rotorcraft Manufacturers will benefit from first principles-based designing of complex products -Automotive, tracked vehicle industry ...

... Accession Number : ADA528393. Title : Cloud Effects in Hyperspectral Imagery from First-Principles Scene Simulations. ...

... Title : A First Principles Examination of Phase Stability in FCC-Based Ni-V Substitutional Alloys. Descriptive Note : Journal article,. ...

The three independent elastic shear constants of beryllium are calculated from a first principle pseudopotential method. (Author)

We present a first-principles based multiscale modeling approach to heterogeneous catalysis that integrates first-principles kinetic Monte Carlo simulations of the surface reaction chemistry into a fluid dynamical treatment of the macroscale flow structures in the reactor. The approach is applied to a stagnation flow field in front of ...

The structural phase transitions and the fundamental band gaps of MgxZn1 xO alloys are investigated by detailed first-principles calculations in the entire range of Mg concentrations x, applying a multiple-scattering theoretical approach (Korringa-Kohn-Rostoker method). Disordered alloys are treated within the coherent-potential approximation. The ...

We study the description of charge-transfer excitations in a series of coumarin-based donor-bridge-acceptor dyes. We show that excellent predictive power for the excitation energies and oscillator strengths in these systems is obtained by using a range-separated hybrid functional within the generalized Kohn-Sham approach to time-dependent density functional theory. Key to this ...

Adhesion physics was relegated to the lowest echelons of academic pursuit until the advent of three seemingly disconnected events. The first, atomic force microscopy (AFM), eventually allowed fine-scale measurement of adhesive point contacts. The second, large-scale computational materials science, now permits both hierarchical studies of a few thousand atoms from first ...

Predicting the domain structures and properties in both bulk single crystal and thin film ferroelectrics using the phase-field approach requires the knowledge of fundamental mechanical, electrical, and electromechanical coupling properties of a single-domain state. In this work, the elastic properties and structural parameters of cubic single crystals as well as tetragonal, ...

We present first-principles electronic structure calculations of Mn-doped III-V semiconductors based on the local spin-density approximation (LSDA) as well as the self-interaction corrected local spin-density method (SIC-LSD). We find that it is crucial to use a self-interaction free approach to properly describe the electronic ground state. The SIC-LSD ...

In this talk, we describe recent efforts using first-principles density functional theory (DFT) based methods to elucidate the reaction energetics and phase stability in the Li-B-N-H hydrogen storage system. We have calculated DFT total energies of a large number of phases in this system, including Li4BN3H10, Li2BNH6, and their decomposition products. We then use these DFT ...

It is well-known that the (110) surfaces of late 5d transition metals (e.g. Au, Pt) undergo a (1x2) missing-row reconstruction, while clean surfaces of 3d and 4d metals (e.g. Cu, Ag) do not. Here, we report the use of a cluster expansion (CE) approach to study this particular class of ``missing-row'' surface reconstructions of some transition metals. We have used ...

We present first-principles electronic structure calculations of Mn doped III-V semiconductors based on the local spin-density approximation (LSDA) as well as the self-interaction corrected local spin density method (SIC-LSD). We find that it is crucial to use a self-interaction free approach to properly describe the electronic ground state. The SIC-LSD ...

We present a recently developed approach to calculate electron-hole excitations and the optical spectra of condensed matter from first principles. The key concept is to describe the excitations of the electronic system by the corresponding one- and two-particle Green's function. The method combines three computational ...

In the teaching of calculus, the algebraic derivation of the derivative (gradient function) enables the student to obtain an analytic "global" gradient function. However, to the best of this author's knowledge, all current technology-based approaches require the student to obtain the derivative (gradient) at a single point by implementing differentiation using ...

First-principles calculations offer a useful complement to experimental approaches for characterizing hydrogen permeance through dense metal membranes. A challenge in applying these methods to disordered alloys is to make quantitative predictions for the net solubility and diffusivity of interstitial H based on the spatially local information that can be ...

of the codes used in TCM (CASTEP, CRYSTAL, PARATEC, ONES, CASINO, GAUSSIAN, CPMD) can do this. Codes which can include: � ABINIT (pseudopotential plane�wave DFT) www.mapr.ucl.ac.be/ABINIT/ � WIEN (FLAPW DFT) www.wien2.uam.es/departamentos/ciencias/fismateriac/siesta/ � VASP (pseudopotential plane�wave/PAW DFT) cms.mpi.univie.ac.at/vasp/ � ...

We review the development and application of kinetic Monte Carlo simulations to investigate defect and dopant diffusion in ion implanted silicon. In these type of Monte Carlo models, defects and dopants are treated at the atomic scale, and move according to reaction rates given as input principles. These input parameters can be obtained from first ...

It is essential to know the arrangement of the atoms in a material in order to compute and understand its properties. Searching for stable structures of materials using first-principles electronic structure methods, such as density-functional-theory (DFT), is a rapidly growing field. Here we describe our simple, elegant and powerful approach to searching ...

A pragmatic approach is presented to the on-orbit calibration of the spaceborne gimbaled parabolic reflector antennas to enhance their pointing and tracking accuracies in the presence of unknown structural deformations and other errors. The technique described is based on the second-order extended Kalman filter. Except for some knowledge of Kalman filtering, the work is ...

We compute, from first principles, the frequency of the E(2g), Gamma phonon (Raman G band) of graphene, as a function of the charge doping. Calculations are done using (i) the adiabatic Born-Oppenheimer approximation and (ii) time-dependent perturbation theory to explore dynamic effects beyond this approximation. The two approaches ...

The goal of multiscale modelling of heterogeneous catalytic reactors is the prediction of all steps, starting from the reaction mechanism at the active centre, the rates of reaction, adsorption and diffusion processes inside the porous system of the catalyst support, based on first principles, quantum chemistry, force field simulations and macroscopic ...

Organometallic complexes have potential applications as the optically active components of organic light emitting diodes (OLEDs) and organic photovoltaics (OPV). Development of more effective complexes may be aided by understanding their excited state properties. Here we discuss two key theoretical approaches to investigate these complexes: first ...

Laterally resolved measurements of the quantum size effect (QSE) in electron reflectivity are made with low energy electron microscopy on coherently strained Ag films on a W(110) surface. The evolution of the total film thickness with increasing number of atomic layers is determined accurately by dynamical theory analysis of the QSE features. Combined with a model of layer spacings obtained from ...

The effect of the electron-phonon interaction on magnetization relaxation is studied within the framework of first-principles scattering theory for Fe, Co, and Ni by displacing atoms in the scattering region randomly with a thermal distribution. This �frozen thermal lattice disorder� approach reproduces the nonmonotonic damping behavior observed in ferromagnetic resonance ...

We employ a multiscale modeling approach to study the surface structure and composition of a Pd(100) model catalyst in reactive environments. Under gas phase conditions representative of technological CO oxidation (�1atm, 300 600 K) we find the system on the verge of either stabilizing subnanometer thin oxide structures or CO adlayers at the surface. Under steady-state ...

We have developed a hybrid, parallel computer code for calculating the electronic structure of both ordered and substitutionally disordered materials. By using PVM3.3, we can integrate into our local computer environment multiple parallel and vector supercomputers as well as high performance workstations. Without this approach, calculations of materials properties of large ...

We have developed a hybrid, parallel computer code for calculating the electronic structure of both ordered and substitutionally disordered materials. By using PVM3.3, we can integrate into our local computer environment multiple parallel and vector superconductors as well as high performance workstations. Without this approach, calculations of materials properties of large ...

First-principles calculations of equation of state and single-crystal elastic constants of copper are carried out up to twofold compression. The Helmholtz free energies are calculated using the quasi-harmonic phonon approach based on density-functional theory within both the local density approximation and the generalized gradient approximation (GGA). We ...

The electronic and structural properties of the oxygen vacancy (VO) in cubic BaTiO3 are studied using first-principles calculations based on a hybrid Hartree-Fock density functional approach. Our calculations identify the double shallow donor behavior of VO, indicating its contribution to the n-type conductivity. In addition, a metastable configuration is ...

A recently developed chemical shift anisotropy amplification solid-state nuclear magnetic resonance (NMR) experiment is applied to the measurement of the chemical shift tensors in three disaccharides: sucrose, maltose, and trehalose. The measured tensor principal values are compared with those calculated from first principles using density functional ...

It is essential to know the arrangement of the atoms in a material in order to compute and understand its properties. Searching for stable structures of materials using first-principles electronic structure methods, such as density-functional-theory (DFT), is a rapidly growing field. Here we describe our simple, elegant and powerful approach to searching ...

One of the primary areas of application of artificial intelligence is diagnosis. Diagnosis from first principles is a diagnostic technique which uses knowledge of the designed structure and function of a device to determine the possible causes of the malfunction. This work builds on the foundation of a theory of diagnosis by implementing and extending the ...

Synthetic maps of human gene frequencies, which are maps of principal component scores based on correlation of interpolated surfaces, have been popularized widely by L. Cavalli-Sforza, P. Menozzi, and A. Piazza. Such maps are used to make ethnohistorical inferences or to support various demographic or historical hypotheses. We show from first principles ...

The generalized likelihood ratio (GLR) technique performs statistical tests on the innovations sequence of a Kalman filter state estimator. Using the results of these tests, failures in the sensors of a pressurized water reactor pressurizer are detected and identified. A third-order, linear model of the pressurizer dynamics, which is required by both the GLR and Kalman filter formulations, is ...