... Title : AB Initio Study of the Electronic Magnetic Circular Dichroism ... functions are determined using as initio quantum chemical techniques including ...
DTIC Science & Technology
We report on the determination of a high quality ab initiu potential energy surface (PES) and dipole
NASA Technical Reports Server (NTRS)
Two approaches for directly computing a molecular heat of formation based on sophisticated ab initio
The results of an ab initio determination of the rate of constant for H+H/sub 2/CO are presented. (AIP)
Energy Citations Database
... the potential energy surface provided by modern electronic structure ... screening approach, to determine the equilibrium geometry and composition ...
Ab initio calculations are carried out to determine ?? (true), the first-order contribution to the spin-rotation constant, ??, for the X2? ground states of ...
NASA Website
The number of ab initio molecular electronic calculations has increased dramatically in the last few years. Both the practitioners and other interested students of the results of the calculations have found it increasingly difficult to determine the prese...
National Technical Information Service (NTIS)
The detailed molecular structure of methyl phosphonate, the simplest phosphorus ester, was determined by ab initio quantum-chemical calculations in a variety of basis sets. Computed properties include the optimized structure, dipole moment, number and rel...
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
The nuclear magnetic resonance chemical shift is one of the most powerful properties available for structure determination at the molecular level. A review of advances made in the ab initio calculation of chemical shielding during the past five years is presented. Specifically, progress in the areas including the effects of an unpaired ...
NASA Astrophysics Data System (ADS)
We have studied structural and dynamical properties of Mg2Sn by employing an ab-initio pseudopotential method and a linear response scheme, within the generalised gradient approximation. The calculated lattice constant, bulk modulus and pressure derivative of bulk modulus are in agreement with previous ab-initio calculations and available experimental ...
... This study involves: Ab-initio crystal orbitals and polymer orbitals; Ab-initio coupled cluster program; Ab-initio quantum chemical calculations and ...
Ab initio molecular orbital theory has been used to determine the equilibrium geometries, rotational
powder XRD for fine particle analysis, and single crystal. XRD for coarse materials analysis and ab-initio structure determination. Hybrid-XRD design will ...
... phosphorus species have not been previously determined and were estimated from the results of ab initio quantum chemical calculations available ...
The objective of this research was to investigate fundamental aspects of the fracture and deformation behavior of ordered intermetallic aerospace alloys on the basis of the ab-initio determination of the parameters needed for further (1) model theoretical...
... the PRMD code - in Step 1- will be validated and further studied using ab initio methods to determine kinetic and thermodynamic properties of the ...
Spectroscopic constants and dissociation energies for the ground states of N2, O2, and F2 determined
For some simple, but nontrivial molecular systems, the interaction potentials are now well determined from ab initio electronic structure calculations ...
The unimolecular decay lifetimes of several vibrational states of HN2 are determined on the basis of
Through the use of a molecular pseudopotential method, we determine the a approximate magnitudes of errors that result when electron affinity determinations of polar negative ions are made through ab initio calculations in which the use of a given basis set yields inappropriate values for permanent and induced ...
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 between, are further ...
... Title : Chalcopyrite Magnetic Semiconductors: An Ab-Initio Study of Their Structural, Electronic and Magnetic Properties. ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... COMPENDIUM OF AB INITIO CALCULATIONS ...
... Accession Number : ADA219907. Title : An Ab Initio Study of the Geometry and Rotational Barrier of 4- Phenylimidazole. ...
... from federally funded research, testing and training ... and agencies for Research Development Test and Evaluation ... Title : Ab Initio Calculations of the ...
... Title : Ab Initio Calculation of Vibrational Absorption and Circular Dichroism Spectra Using Density Functional Force Fields. ...
... Title : AB Initio Quantum Chemical Investigations of Solubilities in Supercritical Solutions. Descriptive Note : Conference Paper,. ...
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 clusters, and water AN ...
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 ...
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 ...
The vibrational frequencies of the electronic ground state of resorcinol have been determined via laser-induced dispersed fluorescence spectroscopy. An assignment based on comparison with ab initio calculations on the MP2 and B3LYP (6-311 G (d,p)) level is presented.
The recent literature on the determination of minimum energy conformations by ab initio quantum mechanical techniques is reviewed. The availability of computer-coded analytical first and second derivatives of the Hartree-Fock energy makes possible calculations that will be of significant assistance in structure ...
PubMed Central
We use ab initio crystalline calculations to explore the role of iodine in determining the properties of 1,4-diiodobenzene. The results strongly suggest that the large halogen is an important or perhaps the dominant determinant of the ability of diiodobenzene to transport holes. We conjecture that the high mobility ...
Due to recent advances in methods and computers, the accuracy of ab calculations has reached a point
The phonon dispersion relations of bulk hexagonal boron nitride have been determined from inelastic x-ray scattering measurements and analyzed by ab initio calculations. Experimental data and calculations show an outstanding agreement and reconcile the controversies raised by recent experimental data obtained by electron-energy loss ...
The use of damping functions to correct the multipole expansion at short-range is explored. Damping functions for the terms in the multipole expansion can be determined ab initio as a linear combination of analytic functions of the separation between sites, but there are additional short-range terms that have different angular ...
Vibrational frequency shift upon the 1 : 1 acetone-iodine complex formation was determined from geometries optimized at the SCF (Self Consistent Field) and MP2 (Moeller-Plesset Second Order Perturbation) levels using the ab initio MO (Molecular Orbital) t...
Ab initio molecular orbital theory has been used to examine the kinetics and mechanism for the reaction of chlorine atoms with methyl formate. From the ab initio parameters, the room-temperature rate constant is calculated and found to be in reasonable agreement with the experimental ...
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.
DOE Information Bridge
Ab initio study of ferroelectricity in BaTiO3 nanowires G. Pilania, S. P. Alpay, and R. Ramprasad for axial, trans- verse, and toroidal ferroelectric polarization instabilities in these nanowires have been for ferroelectricity via polarization along the nanowire axis is determined to be 12 �, regardless of the stoichiometry
E-print Network
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 calculations were used to determine the equilibrium geometries and energies of lithium dimethylaminoborohydride. Relative energies of the monomeric and dimeric species were calculated in the gas phase and for the dimethyl ether microsolvated molecules. The most stable structure was a dimer in which the lithium and boron atoms ...
Accurate quartet- and doublet-state potential-energy surfaces for the interaction of a hydrogen atom and an oxygen molecule in their ground states have been determined from an ab initio calculation using large-basis sets and the internally contracted mult...
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 ...
In this work, the structure of symmetric N2O3 was investigated using ab initio methods. Bond lengths and bond angles were determined using the 6-31 G* and the 6-311 G* basis sets using both SCF and MP2 theory. At the highest level of theory considered in ...
The barriers to internal rotation about the N-C bond of formamide and the formanide-H2O complex have been examined by ab initio quantum chemistry methods. Both selfconsistent field and correlated approaches have been utilized to determine the geometries, ...
The detailed molecular structures including the equilibrium conformations and energies of the four prototype phosphorus compounds exhibiting a phosphorus oxygen phosphorous(P-O-P) interconnection, H4P2O2n-1 for n=1 to 4, were determined by ab initio quant...
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 simulations of ...
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 ...
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 ...
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, ...
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 ...
The quadratic, cubic and semi-diagonal quartic force field of propene has been calculated at the MP2 level of theory employing a basis set of triple-? quality. A semi-experimental equilibrium structure has been derived from experimental ground state rotational constants and rovibrational interaction parameters calculated from the ab initio force field. ...
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 (2005)]. Recently, ...
... AB-INITIO SIMULATION OF a/2110> ... 4. TITLE AND SUBTITLE AB-INITIO SIMULATION OF a/2110> SCREW DISLOCATIONS γ-TiAl 5c. ...
... ADP012740 TITLE: Ab Initio Study on Spin Polarization of III-V Compound Tips ... Ab initio study on spin polarization of III-V compound tips ...
Ab initio electronic structure methods can supplement CALPHAD in two major ways for subsequent applications to stability in complex alloys. The first one is rather immediate and concerns the direct input of ab initio energetics in CALPHAD databases. The o...
...with this part. The certificate shall be void ab initio for those vehicles causing the...issued, and the certificate may be deemed void ab initio. (C) The manufacturer...with this part. The certificate shall be void ab initio for those vehicles causing...
Code of Federal Regulations, 2010
Theoretically determined frequencies and absorption intensities are reported for the vibrational spectrum of the covalent HOOOH and hydrogen bonded HO---HOO intermediates that may form in the reaction of the hydroxyl and hydroperoxyl radicals. Basis sets ...
The recently introduced theory of self-consistent electron pairs is shown to be a viable computational method for the determination of ab initio correlated molecular wavefunctions. Features of this method over conventional approaches are presented includi...
Ab initio (MP2/6-31G**//MP2/3-21G) calculations yield a value of about 729 kJ/ mole, ... Quantum chemical; Lubricants; Modelling; Semiempirical; Lubrication; ...
... Abstract : Using ab initio (6-31G(*)) and semiempirical (AM1, PM3) electronic structure calculations and force field (MM3) determinations, we have ...
... Sieves (Eds. ML Occelli and HE Robson), Van Nostrand Reinhard, New York, 1992 p 373. ... Dr. James S. Murday (1) Chemistry Division, Code 6100 ...
The energy difference between silaethylene (H2Si=CH2) and methylsilylene (SiHMe) has been determined with ab initio quantum chemical techniques. Large basis sets and a variety of methods for the inclusion of electron correlation effects have been employed...
The role of various interfaces in deformation and fracture behavior of two phase TiAl-Ti(sub 3)Al alloys is analyzed on the basis of the specific interfacial and surface energies determined from ab initio calculations. The propensity of twinning observed ...
The relaxations of hydrogenated Silicon and Germanium (111) surfaces are determined using ab initio self consistent calculations in a slab configuration. The Si-hydrogen and Ge-H bonds are found to be considerably larger than the sum of covalent radii. Th...
Powder diffraction has developed into an important crystallographic tool over the past thirty years largely because of the success of the Rietveld profile method in structure refinement. The improvements in instrumentation in this period have led to the s...
The fundamental nature of the research was exemplified by ab-initio predictions of the friction coefficient of single crystal diamond sliding against its mating diamond plane, and molecular dynamics calculations on single crystal calcium fluoride and bari...
A method is presented for the ab initio calculation of configuration interaction in many-electron spectra. It is based on the expansion of the total electronic wavefunction in terms of Hartree-Fock-Slater determinants, as calculated by the programs of Her...
Early scattering experiments revealed that the proton was not a point particle but a bound state of many quarks and gluons. Deep inelastic scattering (DIS) experiments have accurately determined the probability of struck quarks carrying a fraction of the ...
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....
The equilibrium structures, harmonic vibrational frequencies, quadratic force fields, dipole moments, and IR intensities of several triatomic bromine compounds of known or potential importance in stratospheric ozone depletion chemistry have been determine...
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 ...
High-level quantum-chemical ab initio coupled-cluster and multiconfigurational perturbation methods have been used to compute the vertical and adiabatic electron affinities of the five canonical DNA and RNA nucleobases: uracil, thymine, cytosine, adenine, and guanine. The present results aim for the accurate determination of the ...
... 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 ...
Ab initio quantum chemical techniques have been used to investigate weakly bund complexes of H20 and SO2. An energy gradient program was used to ...
... 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 ...
... moment has been cancelled a priori for the electronic transition as a function of R(CC), using ab initio quantum chemical techniques including state ...
... Accession Number : ADA440631. Title : Ab Initio Quantum Chemical Study of Electron Transfer in Carboranes. Descriptive Note : Journal article. ...
... Accession Number : ADA270577. Title : Ab Initio Potential Energy Surface for the H + OCS Reaction. Descriptive Note : Final rept. ...
... [2"- ARMY RESEARCH LABORATORY [C Ab Initio Potential Energy Surface for H + OCS Reactions: Extended Basis Sets ...
... Results of this study substantiate findings from an earlier quantum chemical study using a lower ... for (I) and (II) based on the earlier ab initio study. ...
... Ab initio direct trajectory simulation on hydrogen atom transfer in 7-azaindole in the electronic excited state with assist of water molecules ...
... Title : Ab Initio Calculation of Vibrational Circular Dichroism Spectra Using Accurate Post-Self-Consistent-Field Force Fields: trans-2,3 ...
