The H + CO --> HCO reaction has been characterized with correlation consistent basis sets at five
NASA Technical Reports Server (NTRS)
Additivity of Cation- Interactions: An ab Initio Computational Study on -Cation- Sandwich Complexes- sandwiches are the sums of the two corresponding TMA- systems. The contribution of electron correlation- sandwiches and to estimate their binding energies. Morokuma decomposition analysis on the binding energy
E-print Network
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 electron, electron ...
NASA Astrophysics Data System (ADS)
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 ...
... and many-body perturbation theory (MBPT) methods for the accurate inclusion of electron correlation in ab initio quantum chemical calculations of ...
DTIC Science & Technology
... This study involves: Ab-initio crystal orbitals and polymer orbitals; Ab-initio coupled cluster program; Ab-initio quantum chemical calculations and ...
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, ...
PubMed
LDA + DMFT is a novel computational technique for ab initio investigations of real materials with strongly correlated electrons, such as transition metals and their oxides. It combines the strength of conventional band structure theory in the local densit...
National Technical Information Service (NTIS)
Realistic electronic-structure calculations for correlated Mott insulators are notoriously difficult. Here we present an ab initio multiconfiguration scheme that adequately describes strong correlation effects involving Cu 3d and O 2p electrons in layered cuprates. In particular, the O 2p states giving rise to the ...
... 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,. ...
Results of ab initio molecular orbital calculations are reported for complexes of eleven anions with a water molecule. Optimized geometries obtained with the 6-31G(d) basis set were used in calculations including diffuse functions and the correlation energy. The present structural and energetic results complement and extend ...
Energy Citations Database
Ab initio methods are used to study the formation of hydrogen-bonded complexes of cis-1,2-diazene with trans-1,2-diazene, cis-1,2-diazene, and ethylene. These reactions have negligible activation enthalpies when the effects of electron correlation are included. Calculated and experimental free energies of activation are mostly entropic ...
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, ...
Ab initio calculations using extended basis sets are presented for the potential energy surface (PES) of H + OCS. There are two major reaction channels on the PES; Reaction (I) is H(2S) + OCS(1(Sigma)) yields OH(2(Pi)) + CS(1(Sigma)), and Reaction (II) is...
We report a highly correlated multireference configuration interaction calculation of the near-equilibrium potential energy surface of ozone using a large correlation consistent basis set. Three-dimensional analytical expressions are obtained for the potential energy and dipole moment functions using least-squares fits to ab ...
... 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 order to apply ab initio wave-function-based correlation methods to metals, it is desirable to split the calculation into a mean-field part and a correlation part. Whereas the mean-field part (here Hartree-Fock) is performed in the extended periodic system, it is necessary to use for the ...
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...
Contents: Ab Initio Powder Diffraction; Alloys; Amorphous Materials; Aqueous Solutions; Atomic Spectroscopy; Biological Spectroscopy; Biominerals; Catalysts; Ceramics and Glass; Chemistry; Coherence/Correlation in Innershell Processes; Combined Techniques...
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...
Under AFOSR support over several years, coupled-cluster (CC) and many-body perturbation theory (MBPT) methods for the accurate inclusion of electron correlation in ab initio quantum chemical calculations of molecules have been definitively established as ...
Ab initio calculations of valence shell ionization potentials have shown that orbital relaxation and correlation differences usually make contributions of comparable magnitude. In marked contrast to this observation is the situation for deep core ionizati...
Group of Young Researchers 'Quantum Chemistry' (Dr. M. Dolg) The group of young researchers 'Quantum Chemistry' works on quantitative ab initio electronic structure calculations for properties of relativity and electron correlation are investigated and interpreted. A major area of research
Assisted by prior ab initio correlated predictions of the vibrational spectral, the first experimental observation of the H2-BH3 complex was recently reported by Tague and Andrews (TA). However, H2-BH3 has been calculated to have Cs symmetry, following th...
Ab initio quantum chemical calculations are presented for the energy of dimerization of the borane molecule (2BH3 B2H6). The calculations are superior to previous theoretical treatments both in the level of treatment of electron correlation and in the one...
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 \
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...
Refined ab initio calculations on the dehydration and decarboxylation mechanisms of formic acid in the gaseous state above 670/sup 0/C are presented, taking into account the effect of electron correlation on both the geometries and energies of the different stationary points. The classical barrier heights of the two processes are much ...
The nature of intermolecular interactions between aromatic amino acid residues has been investigated by a combination of molecular dynamics and ab initio methods. The potential energy surface of various interacting pairs, including tryptophan, phenilalanine, and tyrosine, was scanned for determining all the relevant local minima by a combined molecular ...
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 the solvent described ...
The ability of simple levels of ab initio molecular orbital theory to describe with reasonable accuracy the energetics of isotopic exchange processes is demonstrated. Three levels of ab initio molecular orbital theory have been surveyed. The first two levels are single-determinant Hartree-Foch methods utilizing the ...
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 ground state and ...
Results from several commonly used approximate methods of evaluating electrostatic interactions have been compared to the rigorous, nonexpanded electrostatic energies at both uncorrelated and correlated levels of theory. We examined a number of energy profiles for both hydrogen bonded and stacked configurations of the nucleic acid base pairs. We found that the penetration ...
Ab initio calculations have been performed at the SCF level in the STO-3G, 3-21G, and 6-31G* basis sets on a variety of benzenoid and nonbenzenoid aromatic hydrocarbons, ranging from benzene to coronene. It is shown that (1) the enthalpy changes for homodesmic reactions involving only benzenoid aromatics can be computed accurately in all three bases and ...
We have carried out self-consistent reaction field (SCRF) calculations on the bacteriochlorophyll (BChl) and bacteriopheophytin (BPh) molecules at the Hartree-Fock level using the ab initio electronic structure code PSGVB together with an accurate numerical Poisson-Boltzmann solver. These are by far the largest ab ...
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. ...
... 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
Recently presented nonrelativistic and quasirelativistic energy-adjusted ab initio pseudopotentials, semiempirical core polarization potentials and energy-optimized valence basis sets for the elements Hg to Rn have been applied in molecular calculations on selected hydrides of mercury through astatine and the fluorides of radon. Spin-orbit interaction was ...
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, ...
We perform coupled-cluster and diffusion Monte Carlo calculations of the energies of circular quantum dots up to 20 electrons. The coupled-cluster calculations include triples corrections and a renormalized Coulomb interaction defined for a given number of low-lying oscillator shells. Using such a renormalized Coulomb interaction brings the coupled-cluster calculations with triples ...
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 ...
The results of ab initio slab calculations of surface relaxations, rumplings and charge distribution for the different terminations of the MgF2 (011) and (111) polar surfaces are presented and discussed. We have employed the computer code CRYSTAL with the Gaussian basis set and the hybrid B3PW exchange-correlation functional. Despite ...
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. The effect of ...
... ADP023770. Title : ab-Initio Molecular Dynamics Simulations of Molten Ni-Based Superalloys. Descriptive Note : Conference paper. ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... of Molecular Modelling and Ab initio Molecular ...
... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : New AB Initio Based Density ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... Title : Development of Ab-initio Multibody ...
... Ab initio Energies Calculated Using 3 ... of the Transition States (TS ... Descriptors : *TRANSITIONS, *MOLECULES, COMPUTATIONS, COMPARISON ...
... Abstract : Results are presented from ab initio quantum chemical calculations on the ground state potential energy surface for the open shell ...
... from federally funded research, testing and training ... and agencies for Research Development Test and Evaluation ... Title : An Ab Initio Study of Solid ...
... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : An AB Initio Study of Dimethyl ...
... Accession Number : ADA523968. Title : Ab-initio Simulations of Molten Ni Alloys. Descriptive Note : Journal article (preprint). ...
... Title : Ab-Initio Molecular Dynamics Simulations of Molten Ni-Based Superalloys. Descriptive Note : Conference paper (preprint). ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... Title : Ab-Initio Molecular Dynamics Simulations ...
... We carried out ab-initio quantum chemical calculations on these energetic cyclic ethers and generated the electrostatic molecular potential contour ...
Ab initio quantum chemical techniques have been used to investigate weakly bund complexes of H20 and SO2. An energy gradient program was used to ...
NASA Website
... Accession Number : ADA351780. Title : Ab Initio and DFT Potential Energy Surfaces for Cyanuric Chloride Reactions. Descriptive Note : Final rept. ...
... Ab initio study on atomic structures and physical properties of CdSe quantum nanodots ... Figure 2. Diagram of covered nanodots. ...
... Title : Ab Initio Study on Atomic Structures and Physical Properties of CdSe Quantum Nanodots. Descriptive Note : Final rept. ...
... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : Ab Initio Study of the Structure ...
... Rydberg I 'Flu state. Demoulin and Jungen (1974) used an ab initio quantum chemical approach, but only at the SCF level ...
... moment has been cancelled a priori for the electronic transition as a function of R(CC), using ab initio quantum chemical techniques including state ...
... from federally funded research, testing and training ... and agencies for Research Development Test and Evaluation ... Title : Ab Initio Study of Ultracold ...
1 AB INITIO STUDIES ON HEXAVALENT PHOSPHORUS COMPOUNDS Ashley L. Wilson* Aberdeen High School Aberdeen, Maryland 21001 ...
... Accession Number : ADA436055. Title : Ab Initio Studies on Hexavalent Phosphorus Compounds. Descriptive Note : Conference paper. ...
... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : Ab Initio Relativistic Study of ...
... Accession Number : ADA440631. Title : Ab Initio Quantum Chemical Study of Electron Transfer in Carboranes. Descriptive Note : Journal article. ...
... Accession Number : ADA270577. Title : Ab Initio Potential Energy Surface for the H + OCS Reaction. Descriptive Note : Final rept. ...
... [2"- ARMY RESEARCH LABORATORY [C Ab Initio Potential Energy Surface for H + OCS Reactions: Extended Basis Sets ...
... Results of this study substantiate findings from an earlier quantum chemical study using a lower ... for (I) and (II) based on the earlier ab initio study. ...
... Ab initio direct trajectory simulation on hydrogen atom transfer in 7-azaindole in the electronic excited state with assist of water molecules ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... Title : Ab Initio Direct Trajectory Simulation on ...
... Title : Ab Initio Calculation of Vibrational Circular Dichroism Spectra Using Accurate Post-Self-Consistent-Field Force Fields: trans-2,3 ...
... from federally funded research, testing and training ... for Research Development Test and Evaluation ... Title : Ab Initio Calculation of Intermolecular ...
... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : AB Initio Propagator Theory of ...
We present a generalized definition of subspace occupancy matrices in ab initio methods for strongly correlated materials, such as DFT+U (density functional theory + Hubbard U) and DFT+DMFT (dynamical mean-field theory), which is appropriate to the case of nonorthogonal projector functions. By enforcing the tensorial consistency of all ...
Our program concerns the theoretical investigations of the dynamic effects of relativity and electron correlations on atomic processes, and the developments of relativistic many-body techniques for atomic structure calculations. Currently, we are studying atomic hyperfine structures (hfs) with the multiconfiguration Dirac-Fock (MCDF) technique. This is a very general ...
DOE Information Bridge
We demonstrate a probe for nearest-neighbor correlations of fermionic quantum gases in optical lattices. It gives access to spin and density configurations of adjacent sites and relies on creating additional doubly occupied sites by perturbative lattice modulation. The measured correlations for different lattice temperatures are in good agreement with an ...
Improved estimates of the nonrelativistic stationary nucleus correlation energies of the ground-state atomic ions with three to ten electrons and {ital Z} up to 20 are derived by combining experimental data and improved {ital ab} {ital initio} calculations. Unlike previous work in this area, we focus on the ...
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 energies of the respective atomic ...
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 ...
Molecular mechanics valence force field parameters for the sulfonamide group, SO[sub 2]NH, have been derived from ab initio calculations at the RHF/6-31G* level of theory. The force field parameters were designed to be used in conjunction with existing parameters from the MM2/MMP2 force field. The new parameters are demonstrated to accurately reproduce the ...
We report on the determination of a high quality ab initiu potential energy surface (PES) and dipole
Hydrogen bonding in infinite (HF)_infinity and (HCl)_infinity bent (zig-zag) chains is studied using the ab initio coupled-cluster singles and doubles (CCSD) correlation method. The correlation contribution to the binding energy is decomposed in terms of non-additive many-body interactions between the monomers in ...
Recent trends of ab initio studies and progress in methodologies for electronic structure calculations of strongly correlated electron systems are discussed. The interest for developing efficient methods is motivated by recent discoveries and characterizations of strongly correlated electron materials and by ...
Single-determinant ab initio molecular-orbital calculations have been carried out on the series of donor-acceptor complexes A-OH/sub 2/ (A = Li, Be, B, C, Na, Mg, Al) in their ground and certain excited states. Equilibrium A-O distances, dissociation energies, dipole moments, and some vibrational frequencies have been determined. Dissociation energies are ...
The S/sub N/2 reaction between ammonia and formic acid has been studied as a model reaction for peptide bond formation using the semiempirical MNDO and ab initio molecular orbital methods. Two reaction mechanisms have been examined, i.e., a stepwise and a concerted reaction. The stationary points of each reaction including intermediate and transition ...
Time-dependent density functional theory (TD-DFT) and correlated ab initio methods have been applied to the electronically excited states of vitamin B12 (cyanocobalamin or CNCbl). Different experimental techniques have been used to probe the excited states of CNCbl, revealing many issues that remain poorly understood from an electronic ...
The interaction-induced contribution to the NMR shielding constants in homonuclear A2 and heteronuclear AB (A,B=He,Ne,Ar) dimers is obtained ab initio by employing a coupled cluster singles and doubles with perturbative treatment of triples wave function model and extended correlation-consistent basis sets. The ...
We report ab initio calculations of the electronic and magnetic properties of small Co clusters. We performed pseudopotential-based and all-electron calculations. In view of the ``unwritten theorem'' that electron localization enhances the electronic correlations, we have also considered the LDA+U functional, which is tailored for the ...
