... Title : Ab Initio Calculation of Vibrational Absorption and Circular Dichroism Spectra Using Density Functional Force Fields. ...

... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : New AB Initio Based Density ...

The adsorption energies of methane and ethane in zeolites are investigated with ab initio molecular orbital theory and density functional theory. In this work we have used zeolite cluster models containing two, three, and five tetrahedral (Si, Al) atoms a...

... Abstract : This report describes the development and application of ab initio quantum chemical methods that are especially relevant to the study of ...

... atoms in fullerene and diamond nanocrystallite, respectively, are proposed and examined with ab-initio local density functional method for possible . ...

This study involves: Ab-initio crystal orbitals and polymer orbitals; Ab-initio coupled cluster program; Ab-initio quantum chemical calculations and electrostatic molecular potential contour maps for cationic polymerization; Prediction of crystal density;...

An ab initio centroid molecular dynamics (CMD) method is developed by combining the CMD method with the ab initio molecular orbital method. The ab initio CMD method is applied to vibrational dynamics of diatomic molecules, H2 and HF. For the H2 molecule, the temperature ...

the possible existence of high mass neutron star observations favors a stiff EoS. Ab initio calculations initio calculations of the nuclear many�body problem predict a density and isospin behavior of the Eo. The predictive power of such density functionals at supra�normal ...

... of ab initio quaru cheiial methtods Lhat are espe,,.ally relevant to the study of high-energy density materials species. Two major quantum chemical ...

... dependent densities in the multicomponent RENE-N4 superalloy, and estimates of the accuracy of the Mukai model for liquid density in this system ...

... Title : A Comparative Study of Nonlocal Density Functional Theory and ab initio Methods: The Potential Energy Surface of sym-Triazine Reactions. ...

Structural and thermal properties of small lithium clusters are studied using ab initio-based Monte Carlo simulations. The ab initio scheme uses a Hartree-Fock/density functional treatment of the electronic structure combined with a jump-walking Monte Car...

... nanotubes. We performed ab-initio density functional calculations and studied the optical properties of aligned SWNTs that form carbon nanotube ...

... Abstract : The objectives of this work which were fulfilled were to (1) use high level ab initio molecular orbital theory to predict the structures and ...

... Abstract : The results of ab initio calculations based on the density-functional method and using the norm-conserving pseudopotentials for the ...

respectively, are proposed and examined with ab-initio local density functional method for possible applications as single quantum bits (qubits) in ...

... Spectroscopy of Polyatomic Hydrogen Ions; Measurement of Charge Transfer Between D3 ... Ab Initio Calculations On High Spin States ...

... pressure regions where dissociation, ionization, and elec ... different ab initio, DFT, or semiempirical potentials. The reference potential could rely on a ...

... including superlattice, nanoparticles, and piezoelectric oxide supported metal. To perform this research, we will use ab-initio density functional ...

... atoms in fullerene and diamond nanocrystallite, respectively, are proposed and examined with ab-initio local density functional method for possible . ...

coupling between two QDs. We first parted the Icosahedral QDs by vaccum and calculated the Total Density

... solidification; Density; Nickel alloys; Liquids; Diffusion-liquid; ... erties of molten Ni-based alloys. The simulation method evolves ionic positions using ...

... At present experimental data for ternary Ni-Al-W alloys is not available, and estimates of the accuracy of the Mukai model for liquid density in this ...

... More recently, extensive calculations on the nitrogen oxides were conducted employing the density functional method (ref 2) in conjunction with a ...

Mar 1, 2011 ... respectively, are proposed and examined with ab-initio local density functional method for possible applications as single quantum bits ...

... atoms in fullerene and diamond nanocrystallite, respectively, are proposed and examined with ab-initio local density functional method for possible . ...

NMR chemical shifts for an L-alanine molecular crystal are calculated using ab initio plane wave density functional theory. Dynamical effects including anharmonicity may be included by averaging chemical shifts over an ensemble of structural configurations generated using molecular dynamics (MD). The time scales required mean that ...

NMR chemical shifts for an L-alanine molecular crystal are calculated using ab initio plane wave density functional theory. Dynamical effects including anharmonicity may be included by averaging chemical shifts over an ensemble of structural configurations generated using molecular dynamics (MD). The time scales required mean that ...

The framework of ab initio density-functional theory (DFT) has been introduced as a way to provide a seamless connection between the Kohn-Sham (KS) formulation of DFT and wave-function based ab initio approaches [R. J. Bartlett, I. Grabowski, S. Hirata, and S. Ivanov, J. Chem. Phys. 122, 034104 ...

Density Functional Theory (DFT) is one of the most used {\\em ab initio} theoretical frameworks in materials science. It derives the ground state properties of multi-atomic ensembles directly from the computation of their one-particle density \

Electron energy-loss spectroscopy has been shown to be a powerful tool to determine the chemistry and the electronic structure at grain boundaries by analyzing the energy loss near edge structure (ELNES). This paper describes the ability of ab-initio density of state calculations to perform detailed quantitative analysis at interfaces.

We compare calculations of infrared (IR) spectra of water confined between non polar surfaces, carried out using ab initio and classical simulations. Ab-initio results show important differences between IR spectra and vibrational density of state, unlike classical simulations. These differences originate from ...

Ab-initio quantum chemical investigations of the mechanism of cationic polymerization; Development, implementation testing of theoretical procedures for prediction of crystal structures and densities; Ab-initio quantum chemical MODPOT/VRDDO/MERGE calculat...

Contents: Ab-initio quantum chemical investigations of the mechanism of cationic polymerization; Development of theoretical procedures for prediction of crystal structures and densities; Ab-initio quantum chemical MODPOT/VRDDO/MERGE calculations on nitro-...

We have calculated molecular geometries and electric polarizabilities for small cadmium selenide clusters. Our calculations were performed with conventional ab initio and density functional theory methods and Gaussian-type basis sets especially designed for (CdSe)(n). We find that the dipole polarizability per atom converges rapidly to ...

Ideal shear strength under superimposed normal stress of cubic covalent crystals (C, Si, Ge, and SiC) is evaluated by ab initio density functional theory calculation. Shear directions in [[Formula: see text

Electrical conductivity data of Al for the densities from normal to a fraction of normal density and temperatures up to a few thousand Kelvin are important inputs for the hydrodynamic simulations of exploding aluminium foils. We have generated conductivity data of aluminium, by using ab-initio molecular dynamics simulations and the ...

... This study involves: Ab-initio crystal orbitals and polymer orbitals; Ab-initio coupled cluster program; Ab-initio quantum chemical calculations and ...

Structural and energetic properties of small, deceptively simple anionic clusters of lithium, Li(n)(-), n = 3-7, were determined using a combination of anion photoelectron spectroscopy and ab initio calculations. The most stable isomers of each of these anions, the ones most likely to contribute to the photoelectron spectra, were found using the gradient ...

Structural and energetic properties of small, deceptively simple anionic clusters of lithium, Lin-, n = 3-7, were determined using a combination of anion photoelectron spectroscopy and ab initio calculations. The most stable isomers of each of these anions, the ones most likely to contribute to the photoelectron spectra, were found using the gradient ...

In this review we present the techniques of ab initio molecular dynamics simulation improved to its current stage where the analysis of existing processes and the prediction of further chemical features and real-world processes are feasible. For this reason we describe the relevant developments in ab initio ...

This report describes the development and application of ab initio quantum chemical methods that are especially relevant to the study of high-energy density materials species. Two major quantum chemical program systems, MESA and BROOKLYN, have been develo...

My efforts in the Density Functional Theory (DFT) project of Dr. Bartlett's research group have been limited to the implementation of analytical energy gradients with respect to nuclear displacement in ACES2. The most immediate benefit of this work is ana...

The object of this research is to characterize, using ab initio quantum mechanical methods, the stabilizing or destabilizing effects of hydrogen and/or oxygen matrices on proposed high energy density molecular (HEDM) systems. In addition, the unimolecular...

� � � SBOP +44 +10 786 796 EDTB -45 +16 416 432 MBPP: mixed-basis pseudopotential method CPMD: Car of this boundary using the ab initio, density functional theory based, mixed-basis pseudopotential method [39- denum and niobium. First, the ab initio mixed-basis pseudopotential (MBPP) ...

Molecular orbital calculations on the nickel pentamer cluster were carried out using ab initio methods as well as density functional methods. The molecular orbital cluster approach using effective core potentials (ECP) was used for the ab initio calculati...

. The previous ab initio results on lattices of K atoms for coordination numbers z 8, 4, and 2 are analyzed these DFT results for K into contact with a simple and physically appealing quantum-chemical model proposed conclusions are given at the end of the paper. II. THEORETICAL METHOD We have performed the ab ...

,3 While much is known about the properties of the low energy NaCl(001) surface and water covered NaCl(001 the properties of ambient liquid water films remains a challenge for both experiment and first the properties of the hitherto mysterious nanoscale water film that covers NaCl(001). From our ab initio

Ab-initio study of zone centre phonons in rare-earth hexaborides, MB6, has been made using self-consistent density functional method based on norm-conserving pseudo-potentials and numerical atomic orbitals as basis set. Calculated values of zone centre phonons are in fair agreement with the experimental results.

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 quenching the dangling ...

The authors have calculated the band structures of organic conductors TTF-TCNQ and {beta}-(BEDT-TTF){sub 2}I{sub 3} using the ab initio plane-wave pseudopotential method within the local-density approximation (LDA). The Fermi-surface shape and the origin of bands near the Fermi level are investigated for each compound.

We have investigated the electronic structure of TTF-TCNQ under uniaxial compression with ab initio plane-wave pseudopotential calculations within the local-density approximation and generalized gradient approximation. Depending on the compression direction, the constituent molecules are deformed in different ways. Along with these ...

Based on ab initio pseudopotential calculations, the results of investigations of the lattice dynamics of silver halides AgHal (Hal = Cl, Br, I) are presented. Equilibrium lattice parameters, phonon spectra, frequency densities and effective atomic-charge values are obtained for all types of crystals under study.

We calculate ab initio values of tight-binding parameters for the f- electron metal Ce and various phases of Si, from local-density functional one-electron Hamiltonian and overlap matrix elements. Our approach allows us to unambiguously test the validity of the common minimal basis and two-center approximations as well as to determine ...

Ab initio and nonlocal density functional theory (DFT) calculations were performed to determine reaction mechanisms for formation of the six- membered ring C3N3Cl3 (cyanuric chloride) from the monomer, cyanogen chloride (ClCN). MP2 geometry optimizations ...

... 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 Quantum Chemical Investigations of Solubilities in Supercritical Solutions. Descriptive Note : Conference Paper,. ...

An accurate and efficient molecular alignment technique is presented based on first principle electronic structure calculations. This new scheme maximizes quantum similarity matrices in the relative orientation of the molecules and uses Fourier transform techniques for two purposes. First, building up the numerical representation of true ab initio ...

The structural, electronic and dynamic properties of cesium chloride, ZrRu and ZrZn were studied by employing an ab initio pseudopotential method and a linear response scheme, within the generalized gradient approximation. The calculated lattice constant, bulk modulus and first-order pressure derivative of the bulk modulus were reported in B2 structure and ...

... Title : AB Initio Study of the Electronic Magnetic Circular Dichroism ... functions are determined using as initio quantum chemical techniques including ...

Due to recent advances in methods and computers, the accuracy of ab calculations has reached a point

In this work we show how the ab initio determination of van der Waals coefficients within time-dependent density functional theory can be used to build efficient and accurate atomistic models that describe the long-range interactions of proteins with other proteins and of proteins with semi-conducting surfaces. The model parameters are ...

We build an "all-electron" norm-conserving pseudopotential for boron which extends the use of ab initio molecular dynamics simulations up to 50 times the normal density rho0. This allows us to perform ab initio simulations of dense plasmas from the regime where quantum mechanical effects are ...

We build an 'all-electron' norm-conserving pseudopotential for boron which extends the use of ab initio molecular dynamics simulations up to 50 times the normal density {rho}{sub 0}. This allows us to perform ab initio simulations of dense plasmas from the regime where quantum ...

We report herein a series of ab initio simulations of water under both static and shocked conditions. We have calculated the coherent x-ray scattering intensity of several phases of water under high pressure, using ab initio Density Functional Theory (DFT). We provide new atomic scattering form ...

We studied the optical properties of aligned carbon nanotube mats for photonic device applications. We employed ab-initio density functional calculations in the linear combination of atomic orbital formalism. The calculated dielectric functions of the sem...

We present a method for the computation of cohesive and structural properties of solids. The method is based on a local orbital description of the wavefunctions, an ab initio pseudopotential construction for the ion-core potential, and a local density tre...

The objectives of this work which were fulfilled were to (1) use high level ab initio molecular orbital theory to predict the structures and energies of potential energetic molecules and to guide the synthesis of the more promising candidate molecules, (2...

Inelastic neutron scattering, density functional theory, ab initio molecular dynamics, and classical molecular dynamics were used to examine the behavior of nanoconfined water in palygorskite and sepiolite. These complementary methods provide a strong bas...

Presented here are results of ab initio Density Functional Theory (DFT) structural relaxations performed on dehydrogenated and monohydrogenated nanocrystalline diamond structures of octahedral (111) and cuboctahedral morphologies, up to approximately 2nm ...

Ab initio, the point reactor kinetics has been derivd systematically with an assumption of separation of neutron number density, into a shape-function and a time-function. The understanding of the actual approach of the phenomena is aimed at by a systemat...

The oxidation of the trichlorooxyphosphorus anion (POCl3(-)), which takes place in combustion flames, has been examined experimentally at a variety of temperatures and theoretically via ab initio and density functional methods. The reaction was examined i...

Some of the approaches toward obtaining an understanding of alloy phase stability within the context of ab initio density functional theory are discussed. Recent results of calculations, using the concentration functional theory of Gyorffy and Stocks, of ...

A multiscale technique is developed that couples empirical molecular dynamics (MD) and ab�initio density functional theory (DFT). An overlap handshaking region between the empirical MD and ab�initio DFT regions is formulated and the interaction forces between the carbon atoms are calculated based on the second-generation reactive ...

An earlier calculation of hydrocarbon radical hyperfine coupling constants, using the spin-projected unrestricted Hartree Fock (PuHF) method is updated. Unprojected uHF calculations are performed for all the systems studied before. (AIP)

The main goals in the previous grant period have been to develop new, more effective methods for performing accurate ab initio electronic structure calculations and to use these methods for the prediction of molecular structure, bonding and reactivity, es...

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...

... The axial-axial-axial (AAA) and equitorial-equitorial-equitorial (EEE) conformers have C3v symmetry, a symmetry consistent with vapor and beta ...

The transport properties of two ferrocenedithiolate systems with different five-member ring connections have been estimated using the nonequilibrium Green's function formalism of quantum transport and the density functional theory. The results of the calc...

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....

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 ...

Following remarks on the nature and limitations of ab initio solutions, recent advances in polyatomic electronic structure theory are discussed. The article closes with a discussion of the method of molecular-orbitals-ionic states. (Author)

We have calculated the melting temperature of tungsten by two ab initio approaches. The first approach can be divided into two steps. In the first step, we simulate a large coexisting solid and liquid system by the classical embedded-atom method potential and obtain an approximate melting temperature. In the second step, we compute the accurate melting ...

The fully ionized (metallic) hydrogen plasma is studied by [ital ab] [ital initio] molecular dynamics simulations, for classical protons and fully degenerate electrons, in the strong coupling regime of the protons. The calculated ion-electron pair distribution function signals the breakdown of linear screening with decreasing density ...

Density functional theory based ab initio molecular dynamics simulations with explicit inclusion of empirical van der Waals (vdW) corrections of supercritical carbon dioxide have been performed. Significant changes in the intermolecular pair correlation functions of the fluid modeled with the added vdW interactions are observed, ...

Ab initio and density functional theory (DFT) methods at the HF/6-31G*, B3LYP/6-31G*, MP2/6-31G*, and MP2/TZVP levels of theory were applied to the investigation of the relative stability of six fullerene isomers of C32. Full geometry optimization of the systems was carried out and electrostatic potential distributions were calculated. ...

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 ...

Ab initio Hartree--Fock calculations were performed on FeAr and FeAr/sup +/ in order to determine the interaction of both neutral and singly-ionized Fe atoms trapped in Ar, and on ArFeCO and FeCOAr in order to ascertain the effect of an Ar matrix on the FeCO molecule. Quadrupole splittings and isomer shifts are computed using ab ...

We present a combined computational and experimental study on structural and electric properties of recently synthesized heteroaromatic dyes and their simple aggregates. Ab initio and density functional theory calculations are carried out to investigate ground state and excited state properties along with their modulation induced by ...

Recent progress in the ab-initio molecular dynamics method and the power of parallel computing, allow the detailed study of complex chemical reaction of great industrial relevance. We illustrate this unprecedented capability by investigating the second generation Ziegler-Natta catalytic process. In this inhomogeneous catalyst, a polymerization reaction is induced by TiCl4 ...

An ab initio density functional theory-based study of the electronic band structure, the elastic, electric, elastoelectric, and linear and nonlinear optical properties of the new ion conductor LiB6O9F, has been performed. The computed band structure reveals a wide direct band gap. The coefficients of the second order nonlinear ...

An ab initio molecular dynamics (MD) simulation technique employing the Born-Oppenheimer approach in the framework of a Gaussian implementation of Kohn-Sham density functional theory is used to study the gas-phase conformational dynamics of an alanine dipeptide analog. It is found that conformational transformation between C5 and ...

An ab initio study based on local-density-functional (LDF) theory is presented for the chemisorption of hydrogen on the Pd(111) surface. Our calculation uses the Vienna ab initio molecular-dynamics program (VAMP) based on (i) finite-temperature LDF, (ii) exact calculation of the electronic ...

The results of ab initio calculations of the vibronically averaged components of the anisotropic magnetic hyperfine tensor in the low-lying vibronic species of the X2? electronic state of the HCCS radical are reported. The electronically averaged hyperfine coupling constants for hydrogen, deuterium, 13C and 33S are obtained as functions of two bending ...

Point defects in Fe and dilute FeCu alloys are investigated by ab initio calculations based on density functional theory. The relaxed vacancy and interstitial and substitutional Cu atom formation energies are determined as well as some migration energies. The binding energies of various Cu containing defects believed to play an ...

Structural and thermal properties of small lithium clusters are studied using ab initio-based Monte Carlo simulations. The ab initio scheme uses a Hartree-Fock/density functional treatment of the electronic structure combined with a jump-walking Monte Carlo sampling of nuclear configurations. ...

We report an {ital ab initio} evaluation of the surface energy of a simple metal, performed via a coupling-constant integration over the dynamical density-response function. The rapid rate of change of the electron density at the surface is treated exactly. Long-range correlations are treated self-consistently in ...

We present a direct ab initio dynamics study on the kinetics of the hydrogen exchange of methane with a zeolite model. Dynamical calculations are based on the canonical variational transition state theory plus multidimensional semiclassical tunneling corrections. The reaction path information needed for rate calculations was computed by using a nonlocal ...

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 for structures with ...

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 ...

Ab initio band structure calculations have been performed for the spin-orbit interaction effects at the top of the valence bands for GaAs and InSb. Relativistic, norm-conserving pseudopotentials are used with no correction made for the gaps from the local density approximation. The spin-orbit splitting at GAMMA and linear terms in the ...

We study the general problem of mixing for ab initio quantum mechanical problems. Guided by general mathematical principles and the underlying physics, we propose a multisecant form of Broyden�s second method for solving the self-consistent field equations of Kohn-Sham density-functional theory. The algorithm is robust, requires ...

We present ab initio density functional investigations of the atomic and electronic structure of gallium nitride nanodots and nanowires. With increasing diameter, the average Ga-N bond length in the nanostructures increases, as does the relative stability (heat of formation), approaching the values for bulk GaN. As the diameter ...

Zinc oxide is a key material for optoelectronic applications, whose transport properties are typically dominated by the lattice vibrations. We report here the phonon-dispersion relations of wurtzite ZnO at 10 K, as determined by using inelastic neutron scattering. The experimental data are analyzed with the aid of ab initio calculations based on ...

The phonon-dispersion relations of the lightest wurtzite structure compound BeO have been determined from inelastic x-ray scattering (IXS) measurements and analyzed by ab initio calculations. Experimental data and calculations show good agreement and reconcile the existing controversies. The phonon linewidth of the longitudinal-optical phonon along ?-A ...

A comprehensive study of static, dynamic and electronic properties of liquid Al in a thermodynamic state near its triple point was performed by means of 205-particle ab initio molecular dynamics simulations using Kohn-Sham density-functional theory and the Langevin equation of motion. The good agreement of the results with ...

We study the effect of the splitting of neutron and proton effective masses with isospin asymmetry on the properties of the Skyrme energy density functional. We discuss the ability of the latter to predict observables of infinite matter and finite nuclei, paying particular attention to controlling the agreement with ab initio ...

We use ab initio density-functional calculations to study hydrogen-induced disintegration of single-wall and multiwall carbon fullerenes and nanotubes. Our results indicate that hydrogen atoms preferentially chemisorb along lines in sp2 bonded carbon nanostructures, locally weakening the carbon bonds and releasing stress. For ...

A first-principles analysis of ballistic electron emission spectroscopy (BEES) is used to extract hot-electron lifetimes in metals. The lifetimes are computed within an ab initio framework based on density-functional theory and the GW approximation, and are used in a Keldysh Green function approach for the calculation of BEES currents. ...

Essential oils that contain large concentrations of germacrene D are typically accompanied by cadinane sesquiterpenoids. The acid-catalyzed cyclization of germacrene D to give cadinane and selinane sesquiterpenes has been computationally investigated using both density functional (B3LYP/6-31G^*) and post Hartree-Fock (MP2/6-31G^{* *}) ...

A formula to calculate the charge penetration energy that results when two charge densities overlap has been derived for molecules described by an effective fragment potential (EFP). The method has been compared with the ab initio charge penetration, taken to be the difference between the electrostatic energy from a Morokuma analysis ...

The electronic transport properties of monolayer graphene with extreme physical deformation are studied using ab initio calculations. The aim is to explore the influence of physical bending on transport properties and identify the most important geometrical parameter. The transmission spectra are relatively insensitive to the geometrical parameters in ...

The electronic transport properties of monolayer graphene with extreme physical deformation are studied using ab initio calculations. The aim is to explore the influence of physical bending on transport properties and identify the most important geometrical parameter. The transmission spectra are relatively insensitive to the geometrical parameters in ...

The Dzyaloshinskii-Moriya (DM) vectors arising from a fabrication induced perpendicular strain gradient in a film of bcc Fe are calculated by a combination of the ab initio density functional electron theory with a micromagnetic model. It is shown that even for large strain gradients the absolute values of the DM vectors are 1-2 orders ...

The ab-initio calculations based on density functional theory (DFT) are performed for Fe and C in their ground state crystal structures. Heats of formation are then calculated for different Fe-C alloy compounds. The lattice constant (volume), bulk modulus and shear moduli for cementite are determined from the total energy calculations. These material ...

The INS spectra of several azines have been analyzed starting from force constant matrix calculated via ab initio and DFT methods. In order to reproduce both vibrational frequencies and intensities, the initial force constants must be fitted until the spectral profile is reproduced. We have checked the various ways which can be followed by the user in this ...

We regularize the potential distribution framework to calculate the excess free energy of liquid water simulated with the BLYP-D density functional. Assuming classical statistical mechanical simulations at 350 K model the liquid at 298 K, the calculated free energy is found in fair agreement with experiments, but the excess internal energy and hence also the excess entropy are ...

Using ab initio density-functional theory, we study the role of interstitial hydrogen on the energetics of the phase transformation of iron from bcc to hcp along Bain�s pathway. The impurity creates an internal stress field that can be released through a tetragonal distortion of the lattice, promoting the bcc (ferromagnetic) ? fcc ...

Electronically nonadiabatic effects during the chemisorption of hydrogen atoms on an Al(111) surface are simulated ab initio using time-dependent density-functional theory for the electrons in combination with Ehrenfest dynamics for the nuclei. Strongly nonadiabatic effects close to the spin transition of the H atom are identified, and ...

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 for structures with ...

The ferroelectric [001], [011], and [111] instabilities in KNbO3 with up to 12.5 mol% Cu on K or Nb sites, respectively, are investigated using both ab initio density-functional theory and classical interatomic potentials. A doping level of only about 2�4 mol% Cu on K sites enhances the ferroelectric instabilities and induces a ...

The stability of He in hcp-Ti was studied using ab initio method based on density functional theory. The results indicate that a single He atom prefers to occupy the tetrahedral site rather than the octahedral site. The interaction of He defects with Ti atoms has been used to explain the relative stabilities of He point defects in ...

The relaxation of hot hydrogen atoms upon the dissociative adsorption of H2 on Pd(100) was studied by ab initio molecular dynamics simulations based on density functional theory, modeling the full dissociative adsorption process in a consistent manner. In spite of the nonlinear dependence of every single trajectory on the run ...

The Cytochrome P450 superfamily of enzymes are of great interest in pharmacology as they participate in an enormous range of physiological processes including drug deactivation and xenobiotic detoxification. We apply ab initio electronic structure calculations to model the interactions of the haem molecule at the P450 active site with substrate and ...

The atomic-scale processes that control the formation of carbon deposits on Ni catalysts in reforming applications are poorly understood. Ab initio Density Functional Theory calculations have been used to examine several key elementary steps in the complex network of chemical reactions that precedes carbon formation on practical ...

... 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...

The interaction potential energy surface (PES) of H{sub 4} is of great importance for quantum chemistry, as a test case for molecule--molecule interactions. It is also required for a detailed understanding of certain astrophysical processes, namely, collisional excitation and dissociation of H{sub 2} in molecular clouds, at densities too low to be accessible experimentally. ...

The ab initio/classical free energy perturbation (ABC-FEP) method proposed previously by Wood et al. [J. Chem. Phys. 110, 1329 (1999)] uses classical simulations to calculate solvation free energies within an empirical potential model, then applies free energy perturbation theory to determine the effect of changing the empirical solute-solvent interactions ...

The interaction potential energy surface (PES) of H4 is of great importance for quantum chemistry as a test case for molecule-molecule interactions. It is also required for a detailed understanding of certain astrophysical processes, namely collisional excitation and dissociation of H2 in molecular clouds, at densities too low to be accessible experimentally. The 6101 ...

The adsorption energies of methane and ethane in zeolites are investigated with ab initio molecular orbital theory and density functional theory. In this work we have used zeolite cluster models containing two, three, and five tetrahedral (Si, Al) atoms and have found equilibrium structures for complexes of methane, ethane, and propane ...

... ADP023770. Title : ab-Initio Molecular Dynamics Simulations of Molten Ni-Based Superalloys. Descriptive Note : Conference paper. ...

... 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 ...

... Title : Ab-Initio Molecular Dynamics Simulations of Molten Ni-Based Superalloys. Descriptive Note : Conference paper (preprint). ...

... We carried out ab-initio quantum chemical calculations on these energetic cyclic ethers and generated the electrostatic molecular potential contour ...

... 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. ...

... Rydberg I 'Flu state. Demoulin and Jungen (1974) used an ab initio quantum chemical approach, but only at the SCF level ...

... 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 ...

... Ab initio direct trajectory simulation on hydrogen atom transfer in 7-azaindole in the electronic excited state with assist of water molecules ...

... Title : Ab Initio Calculation of Vibrational Circular Dichroism Spectra Using Accurate Post-Self-Consistent-Field Force Fields: trans-2,3 ...