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1
Ab-Initio Simulation of a/2110> Screw Dislocations Gamma ...
2004-11-01

... AB-INITIO SIMULATION OF a/2110> ... 4. TITLE AND SUBTITLE AB-INITIO SIMULATION OF a/2110> SCREW DISLOCATIONS γ-TiAl 5c. ...

DTIC Science & Technology

2
Ab-Initio Molecular Dynamics Simulations of Molten Ni-Based ...
2007-06-01

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

DTIC Science & Technology

3
Ab Initio Direct Trajectory Simulation on Hydrogen Atom ...
2006-07-14

... from federally funded research, testing and training ... for Research Development Test and Evaluation ... Title : Ab Initio Direct Trajectory Simulation on ...

DTIC Science & Technology

4
ab-Initio Molecular Dynamics Simulations of Molten Ni-Based ...
2007-06-01

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

DTIC Science & Technology

5
Ab-initio Simulations of Molten Ni Alloys
2010-04-01

... Accession Number : ADA523968. Title : Ab-initio Simulations of Molten Ni Alloys. Descriptive Note : Journal article (preprint). ...

DTIC Science & Technology

6
Ab-Initio Molecular Dynamics Simulations of Molten Ni-Based ...
2008-07-01

... from federally funded research, testing and training ... for Research Development Test and Evaluation ... Title : Ab-Initio Molecular Dynamics Simulations ...

DTIC Science & Technology

7
Ab Initio Direct Trajectory Simulation on Hydrogen Atom ...
2006-07-14

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

DTIC Science & Technology

8
HFCIT Program Review May 17, 2006

with ultrasoft pseudopotentials as implemented in the VASP (Vienna Ab Initio Simulation Package) software

E-print Network

9
SnO2: BULK AND SURFACE SIMULATIONS BY AN AB INITIO

SnO2: BULK AND SURFACE SIMULATIONS BY AN AB INITIO NUMERICAL LOCAL ORBITALS METHOD A.V. POSTNIKOVa structure of ideal bulk SnO2 is well studied by ab initio calculations (Peltzer y Blanc�a, Svane study of several SnO2 surfaces, com- paring their energies of formation, and started to look

E-print Network

10
Ab-initio Simulations of Molten Ni Alloys
2010-04-01

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

DTIC Science & Technology

11
Potential energy and free energy surfaces of glycyl-phenyalanyl-alanine (GFA) tripeptide: experiment and theory

with molecular dynamic simulations in combination with high level correlated ab initio quantum chemical the existing minima in the PES. 2. Ab initio quantum-chemical calculations. The lowest energy minima (within surface analysis by metadynamics. Gibbs energies and populations obtained from ...

E-print Network

12
Ab initio energy landscape of LiF clusters.
2010-07-14

A global search for possible LiF cluster structures is performed up to (LiF)(8). The method is based on simulated annealing, where all the energies are evaluated on the ab initio level. In addition, the threshold algorithm is employed to determine the energy barriers for the transitions among these structures, for the cluster (LiF)(4), ...

PubMed

13
Ab initio Monte Carlo investigation of small lithium clusters.
1999-01-01

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...

National Technical Information Service (NTIS)

14
Torsional anharmonicity in the conformational thermodynamics of flexible molecules
2005-01-01

We present an algorithm for calculating the conformational thermodynamics of large, flexible molecules that combines ab initio electronic structure theory calculations with a torsional path integral Monte Carlo (TPIMC) simulation. The new algorithm overcomes the previous limitations of the TPIMC method by including the thermodynamic ...

NASA Astrophysics Data System (ADS)

15
Transfer of Training and Simulator Qualification or Myth and Folklore in Helicopter Simulation.
1992-01-01

Transfer of training studies at Fort Rucker using the backward-transfer paradigm have shown that existing flight simulators are not entirely adequate for meeting training requirements. Using an ab initio training research simulator, a simulation of the UH...

National Technical Information Service (NTIS)

16
Generation of Electrical Conductivity Data of Al using Ab-initio Molecular Dynamics simulations
2011-07-01

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 ...

NASA Astrophysics Data System (ADS)

17
Ab initio molecular dynamics simulation of a pressure induced zinc blende to rocksalt phase transition in SiC.
2009-05-26

The high-pressure induced phase transformation from the zinc blende to rocksalt structure in SiC has been studied by the ab initio molecular dynamics method. The simulations showed that SiC passes through a tetragonal intermediate state before transforming to a monoclinic phase at 160�GPa. The mechanism for this phase transformation ...

PubMed

18
Theoretical Kinetic Estimates for the Recombination of ...
2000-08-04

... Abstract : Ab initio quantum chemical simulations were coupled with variational transition state theory in estimating rate constants for the H + C3H3 ...

DTIC Science & Technology

19
Simulation of Thermal Stability and Friction: A Lubricant ...

... The interactions for DTP, DTC and Fe2O3 are evaluated based on a force field derived from fitting to ab initio quantum chemical calculations of ...

DTIC Science & Technology

20
Quantum Molecular Dynamics Simulation of Hypergolic ...
2010-04-01

... For example, ab initio quantum chemical calculations when combined with reaction rate theory and kinetics modeling can, in principle, be capable ...

DTIC Science & Technology

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21
Ab-Initio Molecular Dynamics Simulations of Molten Ni-Based ...
2007-06-01

... 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 ...

DTIC Science & Technology

22
Ab-Initio Molecular Dynamics Simulations of Molten Ni-Based ...
2008-07-01

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

DTIC Science & Technology

23
Dissociation of NaCl in water from ab initio molecular dynamics simulations
2010-03-01

We perform ab initio molecular dynamics simulations to study the dissociation of NaCl in water. The potential of mean force (PMF) between the two ions is determined using the constrained-force method. The simulation windows corresponding to the contact and solvent-separated minima, and the transition state in ...

NASA Astrophysics Data System (ADS)

24
TOPICAL REVIEW: Hydrogen interaction with carbon nanotubes: a review of ab initio studies
2002-05-01

In this paper we review the existing theoretical literature on hydrogen storage in single-walled carbon nanotubes. The importance of theoretical simulations for understanding the adsorption procedure and for improving the storage capacity of these nano-materials is underlined. We report two different categories of theoretical approach used for this purpose, i.e. classical ...

NASA Astrophysics Data System (ADS)

25
Quantum Chemical Investigations of the Mechanism of ...
1983-10-28

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

DTIC Science & Technology

26
Real-World Predictions from Ab Initio Molecular Dynamics Simulations.
2011-08-12

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 ...

PubMed

27
Efficient sampling for ab initio Monte Carlo simulation of molecular clusters using an interpolated potential energy surface.
2009-01-14

An approach is developed to enhance sampling for ab initio Monte Carlo and ab initio path integral Monte Carlo calculations of molecular clusters by utilizing an approximate potential as a guide to move in the configuration space more efficiently. The interpolated potential energy obtained by the moving ...

PubMed

28
An investigation of the local structure and dynamic properties of undercooled liquid silicon using the orbital-free ab-initio molecular dynamics method
2011-05-01

We present results for the static and dynamic structural properties of undercooled liquid Si, at several temperatures between 1550 K and 1100 K, obtained through orbital-free ab-initio molecular dynamics simulations. The local bond angle distributions show a modest increase in the tetrahedral order upon decreasing the temperature. We also analyze the ...

NASA Astrophysics Data System (ADS)

29
Vibrational properties of water under confinement: Electronic effects
2008-10-17

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 ...

Energy Citations Database

30
Molecular simulation of the vapour�liquid phase coexistence of neon and argon using ab initio potentials

Molecular simulation of the vapour�liquid phase coexistence of neon and argon using ab initio are reported for the vapour�liquid phase coexistence of neon and argon. For neon two dierent quantum chemical interactions. In addition calculations are also reported for neon using a potential that includes three

E-print Network

31
AB INITIO MOLECULAR�DYNAMICS SIMULATIONS OF ADSORPTION OF DYE MOLECULES AT SURFACES

and O�H bond length for a simple water molecule and for water in contact with NaCl surfaces. The resultsAB INITIO MOLECULAR�DYNAMICS SIMULATIONS OF ADSORPTION OF DYE MOLECULES AT SURFACES M. SUGIHARA, H molecules on the NaCl(100) surface. The investigations concentrate on the flat dye molecules trimethin, [C

E-print Network

32
Structural investigation of water acetonitrile mixtures: An ab initio, molecular dynamics and X-ray diffraction study
2005-09-01

In this work, we present a study on water acetonitrile (AN) mixtures by molecular dynamics ab initio and X-ray diffraction techniques. Comparison of the experimental total G(r) functions of the mixtures with the results of molecular dynamics simulation shows an overall good agreement. The properties of hydrogen bonded clusters (water ...

NASA Astrophysics Data System (ADS)

33
Melting temperature of tungsten from two ab initio approaches
2011-09-01

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 ...

NASA Astrophysics Data System (ADS)

34
First Principals and Classical Molecular Dynamics Simulations of Solvated Benzene
2007-09-11

We have performed extensive ab initio and classical MD simulations of benzene in water in order to examine the unique solvation structures that are formed. Qualitative differences between classical and ab initio MD simulations are found and the importance of various ...

Energy Citations Database

35
Ab initio molecular dynamics simulations of dense boron plasmas up to the semiclassical Thomas-Fermi regime.
2007-05-31

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 ...

PubMed

36
Ab initio molecular dynamics simulations of dense boron plasmas up to the semiclassical Thomas-Fermi regime
2007-05-15

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 ...

Energy Citations Database

37
Chalcopyrite Magnetic Semiconductors: An Ab-Initio Study of ...
2001-04-01

... Title : Chalcopyrite Magnetic Semiconductors: An Ab-Initio Study of Their Structural, Electronic and Magnetic Properties. ...

DTIC Science & Technology

38
COMPENDIUM OF AB INITIO CALCULATIONS OF ...
1967-12-01

... from federally funded research, testing and training ... for Research Development Test and Evaluation ... COMPENDIUM OF AB INITIO CALCULATIONS ...

DTIC Science & Technology

39
An Ab Initio Study of the Geometry and Rotational Barrier of 4 ...
1990-03-16

... Accession Number : ADA219907. Title : An Ab Initio Study of the Geometry and Rotational Barrier of 4- Phenylimidazole. ...

DTIC Science & Technology

40
Ab Initio Calculations of the Magnetic Anisotropy.
1987-05-01

... from federally funded research, testing and training ... and agencies for Research Development Test and Evaluation ... Title : Ab Initio Calculations of the ...

DTIC Science & Technology

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41
Ab Initio Calculation of Vibrational Absorption and Circular ...
1995-02-01

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

DTIC Science & Technology

42
AB Initio Quantum Chemical Investigations of Solubilities in ...
1992-11-17

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

DTIC Science & Technology

43
Structural stability and magnetic properties of metastable Fe-Cu alloys studied by ab initio calculations and molecular dynamics simulations
2004-02-01

For the equilibrium immiscible Fe-Cu system, ab initio calculations using the projector augmented wave method identify the relatively stable structures of the metastable Fe25Cu75 and Fe50Cu50 alloys to be both of fcc and determine their corresponding lattice constants and cohesive energies. Some of the ab initio ...

NASA Astrophysics Data System (ADS)

44
Towards SiC Surface Functionalization: An Ab Initio Study
2005-01-28

We present a microscopic model of the interaction and adsorption mechanism of simple organic molecules on SiC surfaces as obtained from ab initio molecular dynamics simulations. Our results open the way to functionalization of silicon carbide, a leading candidate material for bio-compatible devices.

DOE Information Bridge

45
Ab initio tensile experiment on a model of an intergranular glassy film in ?-Si3N4 with prismatic surfaces
2009-02-01

We report the results of a large-scale ab initio simulation of an intergranular glassy film (IGF) model in ?-Si3N4. It is shown that the stress-strain behavior under uniaxial load in the model with prismatic surfaces and few defective bonds is very different from an earlier IGF model with basal planes. The results are explained by the ...

NASA Astrophysics Data System (ADS)

46
Ab initio calculations in a uniform magnetic field using periodic supercells
2003-10-21

We present a formulation of ab initio electronic structure calculations in a finite magnetic field, which retains the simplicity and efficiency of techniques widely used in first principles molecular dynamics simulations, based on plane-wave basis sets and Fourier transforms. In addition we discuss results obtained with this method for ...

DOE Information Bridge

47
Ab Initio Determination of Thermal Conductivity of Dense Hydrogen Plasmas
2009-02-20

Ab initio molecular dynamics is used to compute the thermal conductivity of hydrogen at 80 g cm{sup -3} and temperature up to 800 eV. Pressures and ionic structure are compared with orbital-free calculations. Thermal conductivity is evaluated using the Kubo-Greenwood formula and is compared with models currently used in hydrodynamical ...

Energy Citations Database

48
'Ab initio' theory of stimulated rotational Raman scattering and numerical simulation
1988-01-01

An ab initio theory of stimulated rotational Raman scattering is presented which takes into account pump and population depletion, degeneracy effects, multirotational lines, polarization effects, and multiphoton processes. The theory is applied to the case of diatomic molecules. Small signal gain results obtained for N2 are found to agree well with ...

NASA Astrophysics Data System (ADS)

49
ab-Initio Molecular Dynamics Simulations of Molten Ni-Based ...
2007-06-01

... The work presented here makes use of state-of- validated mathematical criteria for predicting the-art AIMD simulations as a means for testing the ...

DTIC Science & Technology

50
Modeling initial stage of ablation material pyrolysis: Graphitic ...

fidelity of the ReaxFF method to simulate phenol formaldehyde resin is performed by comparing the rdf from ReaxFF with ab-initio MD simulations at 300 K. ...

NASA Website

51
Ab initio simulation of atomic-scale imaging in noncontact atomic force microscopy
2009-07-01

In this paper, we summarize some results of our ab initio simulations aimed at investigating the mechanism of the NC-AFM image contrast on semiconductor and metallic surfaces. We start with an introduction into the basic ideas behind the ab initio simulation process of the ...

NASA Astrophysics Data System (ADS)

52
Communication: Thermodynamics of water modeled using ab initio simulations
2010-10-01

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 ...

NASA Astrophysics Data System (ADS)

53
AB Initio Study of the Electronic Magnetic Circular Dichroism ...
1991-01-15

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

DTIC Science & Technology

54
Prediction of the phase behavior of acetonitrile and methanol with ab initio pair potentials. II. The mixture
2002-05-01

The comprehensive study of the ab initio pair potentials and prediction of properties for acetonitrile and methanol [J. Chem. Phys. 116, 7627 (2002), preceding paper] is extended to examine the vapor-liquid equilibria of their mixture. An ab initio pair interaction potential is developed for the ...

NASA Astrophysics Data System (ADS)

55
Modeling of the spin-transfer torque switching in FePt/MgO-based perpendicular magnetic tunnel junctions: A combined ab initio and micromagnetic simulation study
2011-07-01

Combined ab initio and micromagnetic simulations are carried out to build up a direct relationship between critical switching current Jc and geometric structure (in-plane lattice constant a and film thickness) of FePt in magnetic tunnel junctions. Ab initio calculations predict that the strain ...

NASA Astrophysics Data System (ADS)

56
Conformational dynamics of an alanine dipeptide analog: an ab initio molecular dynamics study.
2001-06-18

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 ...

PubMed

57
Ab initio molecular dynamics simulation of pressure-induced zinc blende to rocksalt phase transition in SiC
2009-06-17

The high-pressure induced phase transformation from the zinc blende to rocksalt structure in SiC has been studied by ab initio molecular dynamics. The simulations show that SiC passes through tetragonal and then monoclinic intermediate states before finally forming the rock salt structure at 160 GPa. The mechanism for this phase ...

Energy Citations Database

58
Ab initio Molecular Dynamics Simulations of Water Under Static and Shock Compressed Conditions
2007-07-25

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 ...

DOE Information Bridge

59
Increasing the Time Step with Mass Scaling in Born-Oppenheimer ab initio QM/MM Molecular Dynamics Simulations
2009-12-01

Born-Oppenheimer ab initio QM/MM molecular dynamics simulation with umbrella sampling is a state-of-the-art approach to calculate free energy profiles of chemical reactions in complex systems. To further improve its computational efficiency, a mass-scaling method with the increased time step in MD simulations has ...

PubMed Central

60
Molecular Spectroscopy by Ab Initio Methods
1994-01-01

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

NASA Technical Reports Server (NTRS)

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61
The chemical shift of deprotonated water dimer: Ab initio path integral simulation
2010-03-01

The 1H NMR chemical shift in deprotonated water dimer H3O2- has been studied by ab initio path integral simulation. The simulation predicts that the isotropic shielding of hydrogen-bonded proton increases as a function of temperature by about 0.003 ppm/K. This change is about an order of magnitude larger than that ...

NASA Astrophysics Data System (ADS)

62
Hydrogen bond connectivity in jennite from ab initio simulations
2008-12-15

The protonation scheme and the hydrogen bond connectivity in the structure of jennite were investigated by ab initio molecular dynamics simulations. The calculated statistics of hydrogen bonds at ambient conditions is consistent with the protonation scheme proposed by Bonaccorsi et al. (2004) based on the bond valence theory. The ...

Energy Citations Database

63
Ab initio simulation of the spin transition during chemisorption: H/Al(111).
2006-11-20

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 ...

PubMed

64
Ab initio molecular-dynamics method based on the restricted path integral: Application to the electron plasma and liquid alkali metal
1998-09-01

We introduce an ab initio molecular-dynamics method based on the discretized path-integral representation of quantum particles. Fermi statistics is automatically generated by an effective exchange potential. This path-integral molecular-dynamics method is able to simulate electron plasmas at the border of the degenerate and the ...

NASA Astrophysics Data System (ADS)

65
Ab Initio Simulation of Materials under Extreme Conditions
2005-08-11

The study of materials properties under extreme conditions has made considerable progress over the past decade due to both improvements in experimental techniques and advanced modeling methods. The availability of accurate models is crucial in order to analyze experimental results obtained in extreme conditions of pressure and temperature where experimental data can be scarce. Among theoretical ...

DOE Information Bridge

66
Formamide dimers: a computational and matrix isolation study.
2007-09-21

The dimerization of formamide (FMA) has been investigated by matrix isolation spectroscopy, static ab initio calculations, and ab initio molecular dynamics (AIMD) simulations. Comparison of the experimental matrix IR spectra with the ab initio ...

PubMed

67
Ab initio simulation of collision-induced intensity in the N2 fundamental
2006-12-01

Recent accurate observations [1] of collision-induced absorption (CIA) in the nitrogen and oxygen fundamentals pointed at the existence of the minimum in its integrated intensity temperature variation. This work aims at simulation of the CIA intensity in N2 using quantum chemical complete potential energy and dipole surfaces for N2-N2 system. The absolute magnitude of CIA ...

NASA Astrophysics Data System (ADS)

68
Theoretical Analysis of the CH(3)+H Reaction: Isotope Effects, the High Pressure Limit, and Transition State Recrossing.
2002-01-01

The reaction of methyl radicals with hydrogen atoms is studied with a combination of ab initio quantum chemistry, variational transition state theory, and classical trajectory simulations. The interaction between the two radicals, including the umbrella m...

National Technical Information Service (NTIS)

69
Robert Hazen ? Profile ? Directory ? NASA ... - Astrobiology - NASA

An ab initio study of adsorption of alanine on the chiral calcite (2131) surface . Molecular Simulation, 33:343-351. Bada, J., Fegley, J., Miller, S.L., ...

NASA Website

70
Large-Scale Quantum-Mechanical Simulations of Nanoscale ...
2004-06-01

... Using large scale O(N) real-space-based ab initio calculations, we carried ... and on "designing" new materials with enhanced piezoelectric response. ...

DTIC Science & Technology

71
Key recovery in a business environment

) method as implemented in the Vienna ab initio simulation package VASP (Bl�ochl, 1994; Kresse and Furthm-to-date computational hardware and software. Of the Fe oxides, hematite (-Fe2O3) is the most stable and the most com

E-print Network

72
Electronic Structure and Formation Energy of a Vacancy in Aluminum.
1981-01-01

The electronic structure of a vacancy in Al was calculated self-consistently using norm-conserving ionic pseudopotentials obtained from ab initio atomic calculations. A 27-atom-site supercell containing 1 vacancy and 26 atoms was used to simulate the envi...

National Technical Information Service (NTIS)

73
Calculation of atom-centered partial charges for heme.
1994-01-01

Atom-centered partial charges are calculated for the Fe-heme in cytochrome P450cam for use in molecular dynamics simulations of polar substrates bound in the active site of the enzyme. Charges are fit to the electrostatic potential produced by ab initio U...

National Technical Information Service (NTIS)

74
Biophysical Modeling of Fragment Length Distributions of DNA Plasmids after X and Heavy-Ion Irradiation Analyzed by ...

... has been focused on Monte Carlo simulations of radiation damage in various systems to understand ab initio the mechanisms of physical and chemical events involved in the induction of ... ...

NBII National Biological Information Infrastructure

75
BioMed Central Page 1 of 10

deviation (RMSD) to native fragments of up to 61 residues [10]. Using the ROSETTA program-RMSD ROSETTA simulation, but the central-resolution models for small single-domain proteins. Compared with other ab initio modeling methods such as ROSETTA

E-print Network

76
Ab Initio Study of Excited States of CN- Stabilized in Point-Charge Lattices,
1988-01-01

An MCSCF approach is used to study low lying excited electronic states of CN- and CN in vacuo and in point charge lattices. The latter simulate the electrostatic potential that renders excited states of CN- stable against autoionization in ionic lattices....

National Technical Information Service (NTIS)

77
Ab Initio Study of Excited States of CN- Stabilized in Point-Charge Lattices,
1988-01-01

An MCSCF approach is used to study low lying excited electronic states of CN- and CN in vacuo and in point-charge lattices. The latter simulate the electrostatic potential that renders excited states of CN- stable against autoionization in ionic lattices....

National Technical Information Service (NTIS)

78
[ital Ab] [ital Initio] Molecular Dynamics of Metallic Hydrogen at High Densities
1995-01-30

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 ...

Energy Citations Database

79
Mechanical properties of graphite oxides: Ab initio simulations and continuum theory
2004-12-01

The mechanical properties of oxidized graphitic layers are calculated by atomic ab initio simulations and continuum theory of elasticity. The adsorption of atomic oxygen atoms induces a nanocorrugation as well as a local bonding reinforcement that modify the bending coefficient of a graphite layer. As a matter of fact, a surface oxygen ...

NASA Astrophysics Data System (ADS)

80
Hydrolysis of tetravalent group IV metal ions: an ab initio simulation study.
2010-08-31

Simulations of the tetravalent group IV metal ions, Ge(IV), Sn(IV), and Pb(IV), in aqueous solution were performed using ab initio quantum mechanical charge field molecular dynamics (QMCF MD). The process of hydrolysis, which occurred for each of the metal ions, was analyzed in terms of the time evolution of solvent configuration. ...

PubMed

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81
Development of glue-type potentials for the Al-Pb system: Phase diagram calculation
2000-05-11

Empirical many-body potentials of the glue-type have been constructed for the Al-Pb system using the force matching method. The potentials are fitted to experimental data, physical quantities derived from ab initio linear muffin-tin orbitals calculations and a massive quantum mechanical database of atomic forces generated using ultrasoft pseudopotentials ...

Energy Citations Database

82
Charge carrier motion in disordered conjugated polymers: a multiscale ab-initio study
2009-11-10

We developed an ab-initio multiscale method for simulation of carrier transport in large disordered systems, based on direct calculation of electronic states and electron-phonon coupling constants. It enabled us to obtain the never seen before rich microscopic details of carrier motion in conjugated polymers, which led us to question several assumptions of ...

Energy Citations Database

83
Ab initio simulations of the KrO- anion photoelectron spectra
2002-08-01

The photoelectron spectra of the weakly bound KrO- anion are simulated using a theory which combines the atoms-in-molecule model for molecular electronic wave functions and the Rau-Fano model for photodetachment intensities [J. Chem. Phys. 112, 5852 (2000)]. The nonrelativistic potential energy curves of the anion are obtained from ab ...

NASA Astrophysics Data System (ADS)

84
Ab initio molecular dynamics study of supercritical carbon dioxide including dispersion corrections.
2009-10-14

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, ...

PubMed

85
Ab initio molecular dynamics simulations of the initial stages of solid-electrolyte interphase formation on lithium ion battery graphitic anodes.
2010-05-25

The decomposition of ethylene carbonate (EC) during the initial growth of solid-electrolyte interphase (SEI) films at the solvent-graphitic anode interface is critical to lithium ion battery operations. Ab initio molecular dynamics simulations of explicit liquid EC/graphite interfaces are conducted to study these electrochemical ...

PubMed

86
Ab initio Molecular Dynamics Simulations of the Initial Stages of Solid-electrolyte Interphase Formation on Lithium Ion Battery Graphitic Anodes
2010-09-22

The decomposition of ethylene carbonate (EC) during the initial growth of solid-electrolyte interphase (SEI) films at the solvent-graphitic anode interface is critical to lithium ion battery operations. Ab initio molecular dynamics simulations of explicit liquid EC/graphite interfaces are conducted to study these electrochemical ...

E-print Network

87
Theoretical study on isotope and temperature effect in hydronium ion using ab initio path integral simulation.
2004-09-22

We have applied the ab initio path integral molecular dynamics simulation to study hydronium ion and its isotopes, which are the simplest systems for hydrated proton and deuteron. In this simulation, all the rotational and vibrational degrees of freedom are treated fully quantum mechanically, while the potential ...

PubMed

88
Theoretical study on isotope and temperature effect in hydronium ion using ab initio path integral simulation
2004-09-01

We have applied the ab initio path integral molecular dynamics simulation to study hydronium ion and its isotopes, which are the simplest systems for hydrated proton and deuteron. In this simulation, all the rotational and vibrational degrees of freedom are treated fully quantum mechanically, while the potential ...

NASA Astrophysics Data System (ADS)

89
Decomposing total IR spectra of aqueous systems into solute and solvent contributions: A computational approach using maximally localized Wannier orbitals
2005-06-01

The theoretical principles underpinning the calculation of infrared spectra for condensed-phase systems in the context of ab initio molecular dynamics have been recently developed in literature. At present, most ab initio molecular dynamics calculations are restricted to relatively small systems and short ...

NASA Astrophysics Data System (ADS)

90
Ab initio molecular dynamics simulation of pressure-induced phase transformation in BeO
2011-01-01

Ab initio molecular dynamics (MD) method has been used to study high pressure-induced phase transformation in BeO based on the local density approximation (LDA) and the generalized gradient approximation (GGA). Both methods show that the wurtzite (WZ) and zinc blende (ZB) BeO transforms to the rocksalt (RS) structure smoothly at high pressure. The ...

Energy Citations Database

91
Calculating geochemical reaction pathways--exploration of the inner-sphere water exchange mechanism in Al(H2O)6(3+)(aq) + nH2O with ab Initio calculations and molecular dynamics.
2008-03-27

We have simulated exchange of inner-sphere and bulk water molecules for different sizes of Al3+(aq) clusters, Al(H2O)63+ + nH2O for n = 0, 1, 6, or 12, with ab initio and molecular dynamics simulations, in order to understand how robust the ab initio method is for ...

PubMed

92
Recent advances in jointed quantum mechanics and molecular mechanics calculations of biological macromolecules: schemes and applications coupled to ab initio calculations.
2010-09-27

We review the recent research on the functional mechanisms of biological macromolecules using theoretical methodologies coupled to ab initio quantum mechanical (QM) treatments of reaction centers in proteins and nucleic acids. Since in most cases such biological molecules are large, the computational costs of performing ab ...

PubMed

93
Modeling van der Waals interactions between proteins and inorganic surfaces from time-dependent density functional theory calculations.
2011-07-25

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 fitted so that they ...

PubMed

94
First principles predictions of thermophysical properties of refrigerant mixtures
2011-03-01

We present pair potentials for fluorinated methanes and their dimers with CO2 based on ab initio potential energy surfaces. These potentials reproduce the experimental second virial coefficients of the pure fluorinated methanes and their mixtures with CO2 without adjustment. Ab initio calculations on trimers are ...

NASA Astrophysics Data System (ADS)

95
Exploring complex chemical reactions by ab-initio simulation
1998-03-01

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 ...

NASA Astrophysics Data System (ADS)

96
Determination of NMR chemical shifts for cholesterol crystals from first-principles
2011-03-01

Solid State Nuclear Magnetic Resonance (NMR) is a powerful tool in crystallography when combined with theoretical predictions. So far, empirical calculations of spectra have been employed for an unambiguous identification. However, many complex systems are outside the scope of these methods. Our implementation of ultrasoft and projector augmented wave pseudopotentials within ...

NASA Astrophysics Data System (ADS)

97
Accelerating chemical reactions: exploring reactive free-energy surfaces using accelerated ab initio molecular dynamics.
2011-05-01

A biased potential molecular dynamics simulation approach, accelerated molecular dynamics (AMD), has been implemented in the framework of ab initio molecular dynamics for the study of chemical reactions. Using two examples, the double proton transfer reaction in formic acid dimer and the hypothetical adiabatic ring opening and ...

PubMed

98
Accelerating chemical reactions: Exploring reactive free-energy surfaces using accelerated ab initio molecular dynamics
2011-05-01

A biased potential molecular dynamics simulation approach, accelerated molecular dynamics (AMD), has been implemented in the framework of ab initio molecular dynamics for the study of chemical reactions. Using two examples, the double proton transfer reaction in formic acid dimer and the hypothetical adiabatic ring opening and ...

NASA Astrophysics Data System (ADS)

99
Ab initio calculations of defects in Fe and dilute Fe-Cu alloys
2002-01-01

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 important role in the ...

NASA Astrophysics Data System (ADS)

100
Ab initio calculation of structural, electronic and phonon properties of ZrRu and ZrZn in B2 phase
2011-09-01

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 ...

NASA Astrophysics Data System (ADS)

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101
Ab initio Monte Carlo investigation of small lithium clusters.
1999-06-16

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. ...

Energy Citations Database

102
Hybrid Simulations for the Ion Structure and Dynamics in Dense Plasmas
2009-09-10

We have tested approaches for molecular-dynamics simulations of the ion properties in high-energy-density matter. The scheme incorporates quantum corrections within the potentials used in the classical molecular-dynamics simulation. Thus, a significantly larger number of particles in the simulation box as in ab ...

Energy Citations Database

103
Ab Initio Study on Spin Polarization of III-V Compound Tips
1998-06-01

... ADP012740 TITLE: Ab Initio Study on Spin Polarization of III-V Compound Tips ... Ab initio study on spin polarization of III-V compound tips ...

DTIC Science & Technology

104
AB Initio and Calphad Thermodynamics of Materials.
2004-01-01

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...

National Technical Information Service (NTIS)

105
40 CFR 86.004-30 - Certification.
2009-07-01

...with this part. The certificate shall be void ab initio for those vehicles causing the...issued, and the certificate may be deemed void ab initio. (C) The manufacturer...with this part. The certificate shall be void ab initio for those vehicles causing...

Code of Federal Regulations, 2010

106
Theory, measurements, and modeling of OH and HO2 formation in the reaction of cyclohexyl radicals with O2.
2007-06-11

The production of OH and HO(2) in Cl-initiated oxidation of cyclohexane has been measured using pulsed-laser photolytic initiation and continuous-laser absorption detection. The experimental data are modeled by master equation calculations that employ new G2(MP2)-like ab initio characterizations of important stationary points on the cyclo-C(6)H(11)O(2) ...

PubMed

107
Computer simulation of elastic constants of hydroxyapatite and fluorapatite.
2011-03-09

Hydroxyapatite (HAP) and fluorapatite (FAP) are essential components of dental enamel and bone. In this paper, we report a computational study of the elastic properties of HAP and FAP using ab initio and force field techniques. We have obtained the HAP and FAP elastic stiffness constants in hexagonal symmetry by fitting the Hooke law for both the ...

PubMed

108
Quantum effects on vibrational and electronic spectra of hydrazine studied by "on-the-fly" ab initio ring polymer molecular dynamics.
2009-03-12

Structural and spectroscopic properties of hydrazine, H(2)N-NH(2), it being a floppy or fluxional molecule in a vacuum, are investigated by means of ab initio molecular dynamics, ab initio path integral molecular dynamics, and ab initio ring polymer molecular dynamics ...

PubMed

109
Protonation states in a cobalt-oxide catalyst for water oxidation: fine comparison of ab initio molecular dynamics and X-ray absorption spectroscopy results.
2011-08-01

Ab initio molecular dynamics simulations of a recently proposed cobalt-based catalyst for water oxidation provide insight into the properties of protons at the water/oxide interface. Calculations and X-ray absorption spectroscopy data indicate a cubane-like structure of the catalyst, support the occurrence of protonated ?(2)-O atoms, ...

PubMed

110
Pressure-induced phase transformation in CdO: An ab initio constant-pressure study
2008-12-01

A constant-pressure ab initio technique is used to study the behavior of CdO at high pressures. A phase transformation from the NaCl-type structure to the CsCl-type structure via a rhombohedral intermediate state is successfully observed through the constant-pressure simulation. This phase change is also analyzed from total energy ...

NASA Astrophysics Data System (ADS)

111
Pressure-induced phase transformation SnO2: An ab initio constant pressure study
2008-10-01

We study the behavior of SnO2 under rapid hydrostatic pressures using constant-pressure ab initio simulations. We find that the rutile-type SnO2 transforms into the CaCl2-type structure. At a high pressure of about 20 GPa, a phase transformation into a cubic fluorite-type structure is observed. The orthorhombic Pnma ...

NASA Astrophysics Data System (ADS)

112
Kohn-Sham ab initio molecular dynamics study of liquid Al near melting
2004-10-01

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 ...

NASA Astrophysics Data System (ADS)

113
Catalysis of nanotube plasticity under tensile strain
2002-11-01

We have performed ab initio simulations to investigate the effect of carbon adatoms on the plastic deformation of carbon nanotubes. Under applied stress, the system spontaneously undergoes a Stone-Wales transformation catalyzed by the exchange of the adatom with a substrate atom. The unraveled mechanism reduces the barrier by a factor ...

NASA Astrophysics Data System (ADS)

114
Ab initio theory of Fano resonances in plasmonic nanostructures and metamaterials
2011-06-01

An ab initio theory for Fano resonances in plasmonic nanostructures and metamaterials is developed using the Feshbach formalism. It reveals the role played by the electromagnetic modes and material losses in the system, and enables the engineering of Fano resonances in arbitrary geometries. A general formula for the asymmetric resonance in a ...

NASA Astrophysics Data System (ADS)

115
Ab initio molecular dynamics simulation of structural transformation in zinc blende GaN under high pressure
2010-02-04

High-pressure induced zinc blende to rocksalt phase transition in GaN has been investigated by ab initio molecular dynamics method to characterize the transformation mechanism at the atomic level. It was shown that at 100 GPa GaN passes through tetragonal and monoclinic states before rocksalt structure is formed. The transformation mechanism is consistent ...

Energy Citations Database

116
Ab initio mass tensor molecular dynamics.
2011-01-28

Mass tensor molecular dynamics method was first introduced by Bennett [J. Comput. Phys. 19, 267 (1975)] for efficient sampling of phase space through the use of generalized atomic masses. Here, we show how to apply this method to ab initio molecular dynamics simulations with minimal computational overhead. Test calculations on liquid ...

PubMed

117
Ab initio mass tensor molecular dynamics
2011-01-01

Mass tensor molecular dynamics method was first introduced by Bennett [J. Comput. Phys. 19, 267 (1975)] for efficient sampling of phase space through the use of generalized atomic masses. Here, we show how to apply this method to ab initio molecular dynamics simulations with minimal computational overhead. Test calculations on liquid ...

NASA Astrophysics Data System (ADS)

118
Ab initio calculations of the optical properties of ions in glass
1984-08-01

There is interest in the optical properties of ions in insulating glasses for various applications. This paper addresses the task of predicting optical properties of ions in glass from first principles given only the physics of the constituent atoms. The prospects for developing such ab initio-computation procedures are gleaned from examining the progress ...

Energy Citations Database

119
Ab initio Path Integral Molecular Dynamics Based on Fragment Molecular Orbital Method
2009-10-01

We have developed an ab initio path integral molecular dynamics method based on the fragment molecular orbital method. This �FMO-PIMD� method can treat both nuclei and electrons quantum mechanically, and is useful to simulate large hydrogen-bonded systems with high accuracy. After a benchmark calculation for water monomer, water ...

NASA Astrophysics Data System (ADS)

120
Ab Initio Molecular Dynamics Study of Hot Atom Dynamics after Dissociative Adsorption of H2 on Pd(100)
2009-12-01

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 ...

NASA Astrophysics Data System (ADS)

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121
Comparison of Single Point Ab initio Energies Calculated ...
1989-04-01

... Ab initio Energies Calculated Using 3 ... of the Transition States (TS ... Descriptors : *TRANSITIONS, *MOLECULES, COMPUTATIONS, COMPARISON ...

DTIC Science & Technology

122
An ab initio QCISD Study of the Potential Energy Surface for ...
1998-09-01

... Abstract : Results are presented from ab initio quantum chemical calculations on the ground state potential energy surface for the open shell ...

DTIC Science & Technology

123
Ab-Initio MODPOT/VRDDO/MERGE Calculations on Energetic ...
1981-10-15

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

DTIC Science & Technology

124
Ab initio quantum chemical techniques have been used to ...

Ab initio quantum chemical techniques have been used to investigate weakly bund complexes of H20 and SO2. An energy gradient program was used to ...

NASA Website

125
Ab Initio and DFT Potential Energy Surfaces for Cyanuric ...
1998-07-01

... Accession Number : ADA351780. Title : Ab Initio and DFT Potential Energy Surfaces for Cyanuric Chloride Reactions. Descriptive Note : Final rept. ...

DTIC Science & Technology

126
Ab Initio Study on Atomic Structures and Physical Properties of ...
2009-11-25

... Ab initio study on atomic structures and physical properties of CdSe quantum nanodots ... Figure 2. Diagram of covered nanodots. ...

DTIC Science & Technology

127
Ab Initio Study on Atomic Structures and Physical Properties of ...
2009-11-25

... Title : Ab Initio Study on Atomic Structures and Physical Properties of CdSe Quantum Nanodots. Descriptive Note : Final rept. ...

DTIC Science & Technology

128
Ab Initio Study of the Electric Dipole Transition Moment for the ...
1990-12-01

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

DTIC Science & Technology

129
Ab Initio Study of the Electric Dipole Transition Moment for the ...
1990-12-01

... moment has been cancelled a priori for the electronic transition as a function of R(CC), using ab initio quantum chemical techniques including state ...

DTIC Science & Technology

130
Ab Initio Quantum Chemical Study of Electron Transfer in ...

... Accession Number : ADA440631. Title : Ab Initio Quantum Chemical Study of Electron Transfer in Carboranes. Descriptive Note : Journal article. ...

DTIC Science & Technology

131
Ab Initio Potential Energy Surface for the H + OCS Reaction
1993-10-01

... Accession Number : ADA270577. Title : Ab Initio Potential Energy Surface for the H + OCS Reaction. Descriptive Note : Final rept. ...

DTIC Science & Technology

132
Ab Initio Potential Energy Surface for H + OCS Reactions ...
1994-11-01

... [2"- ARMY RESEARCH LABORATORY [C Ab Initio Potential Energy Surface for H + OCS Reactions: Extended Basis Sets ...

DTIC Science & Technology

133
Ab Initio Potential Energy Surface for H + OCS Reactions ...
1994-11-01

... Results of this study substantiate findings from an earlier quantum chemical study using a lower ... for (I) and (II) based on the earlier ab initio study. ...

DTIC Science & Technology

134
Ab Initio Calculation of Vibrational Circular Dichroism Spectra ...
1996-02-01

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

DTIC Science & Technology

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