... from federally funded research, testing and training ... agencies for Research Development Test and Evaluation ... Title : Ab Initio Relativistic Study of ...
DTIC Science & Technology
Ab initio calculations on polyatomic molecules and solids have progressed to the point that complexes containing any atom in the periodic table can be treated. If a meaningful comparison with experiment is desired, the relativistic terms in the Hamiltonia...
National Technical Information Service (NTIS)
A relativistic pseudopotentional (RPP) for use in ab initio molecular electronic structure calculations is derived in the context of the relativistic effective core potential (REP) method of Lee et al. The resulting atom-specific RPP has salient features ...
... atoms and molecule in order to avoid possible loss of molecules during photoassociation. The result of our investigation is shown in Fig. ...
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)
Multiconfiguration relativistic Dirac-Fock calculations of KLL Auger energies are reported for neon, argon, uranium, and americium. These selected examples demonstrate the feasibility of this method to calculate completely ab initio, in intermediate coupling, Auger transition energies with a precision of a few eV. Comparison of our ...
Energy Citations Database
A theoretical model of Thomson scattering in a magnetized plasma, taking spatial dispersion into account, is developed ab initio. The resulting expressions allow thermal motion to be included in the description of the plasma and remain valid for frequenci...
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
Substantial progress has been made with ab initio relativistic computations of atomic inner-shell energy levels and properties of few-electron ions. A relativistic calculation fo inner-shell ionization by slow protons has been very successful. Threshold-e...
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 ...
... This study involves: Ab-initio crystal orbitals and polymer orbitals; Ab-initio coupled cluster program; Ab-initio quantum chemical calculations and ...
{ital Ab} {ital initio} averaged relativistic effective core potentials (AREP) and spin--orbit (SO) operators are reported for the elements Cs through Rn. Two sets have been calculated for certain elements to provide AREPs with varying core/valence space definitions thereby permitting the treatment of core--valence correlation ...
The theoretical and technical foundations are presented for the efficient relativistic electronic structure theories to treat heavy-atomic molecular systems. This review contains two surveys of four-component and two-component quasi-relativistic approaches. First, we review our highly efficient computational scheme for four-component ...
Auger and Coster--Kronig transition probabilities have been calculated ab initio relativistically from perturbation theory, for frozen orbitals, in the Dirac--Hartree--Slater approach. Results in the j-j coupling scheme are tabulated for > or =22 elements with atomic numbers 18< or =Z< or =96.
Auger and Coster-Kroing transition probabilities have been calculated ab initio relativistically from perturbation theory, for frozen orbitals, in the Dirac-Hartree-Slater approach. Results in the j-j coupling scheme are tabulated for 22 elements with ato...
Ab initio Hartree--Fock calculations were performed on FeAr and FeAr/sup +/ in order to determine the interaction of both neutral and singly-ionized Fe atoms trapped in Ar, and on ArFeCO and FeCOAr in order to ascertain the effect of an Ar matrix on the FeCO molecule. Quadrupole splittings and isomer shifts are computed using ab ...
The structures and relative energies of Pt(PH/sub 3/)XY isomers are investigated with use of ab initio molecular orbital theory and effective potentials. In particular, the cis and trans isomers of the dihydride, dichloride, and hydrochloride are studied. In all cases, the trans isomer is the more stable. Available experimental information is in good ...
Potential energy curves for electronic states of Hg/sub 2/ and TlHg are presented and analyzed. They are derived using large scale configuration interaction procedures for the valence electrons, with the core electrons represented by ab initio relativistic effective potentials. The effect of spin-orbit coupling are investigated for the ...
Ab initio band structure calculations have been performed for the spin-orbit interaction effects at the top of the valence bands for GaAs and InSb. Relativistic, norm-conserving pseudopotentials are used with no correction made for the gaps from the local density approximation. The spin-orbit splitting at GAMMA and linear terms in the ...
... 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,. ...
This work regards the passage of fast electrons through matter, and in particular how electrons scatter and lose energy within a solid. The basic quantum theory of these scattering processes was first considered in the early- to mid-20th century by Bohr, Bethe, Fermi, and others. This work extends our understanding of how a relativistic electron scatters off, and loses energy ...
The energies of the solid reactants in the lead-acid battery are calculated ab�initio using two different basis sets at nonrelativistic, scalar-relativistic, and fully relativistic levels, and using several exchange-correlation potentials. The average calculated standard voltage is 2.13�V, compared with the experimental value of ...
PubMed
The energies of the solid reactants in the lead-acid battery are calculated ab initio using two different basis sets at nonrelativistic, scalar-relativistic, and fully relativistic levels, and using several exchange-correlation potentials. The average calculated standard voltage is 2.13 V, compared with the ...
Resonance fluorescence of laser-driven highly charged ions is investigated with regard to precisely measuring atomic properties. For this purpose an ab initio approach based on the Dirac equation is employed that allows for studying relativistic ions. These systems provide a sensitive means to test correlated ...
The Beutler-Fano autoionizing resonances in the rare-gas atoms argon, krypton, and xenon are studied using the relativistic multichannel quantum-defect theory (MQDT). Dynamical parameters for the MQDT analyses are obtained from an ab initio relativistic-random-phase-approximation calculation. The position and ...
The importance of relativistic effects on chemical and spectroscopic properties of molecules containing very heavy atoms is considered. Recent developments that combine large scale ab initio multiconfiguration self-consistent field/configuration interaction (MCSCF/CI) methods with relativistic configuration ...
... 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
NASA Technical Reports Server (NTRS)
129Xe nuclear shielding tensor is calculated at the leading-order, one-electron Breit-Pauli perturbation theory (BPPT) level for the xenon fluorides XeF+, XeF2, XeF3+, and XeF4 that cover the large nuclear magnetic resonance chemical shift range of this nucleus. BPPT is found to improve the shift range and relative shifts as compared to the nonrelativistic (NR) theory. While the full BPPT ...
The results of valence-only self-consistent field calculations on Hgn+ (n = 0, 1, 2) and HgHn+ (n = 0, 1) using nonrelativistic and quasirelativistic energy-adjusted ab initio pseudopotentials for Hg are compared with corresponding all-electron values from nonrelativistic (Hartree-Fock) and relativistic (Dirac-Fock) atomic as well as ...
A relativistic ab initio model potential (AIMP) for Pt, Au, and Hg atoms has been developed using a relativistic scheme by eliminating small components (RESC) in which the 5p, 5d, and 6s electrons are treated explicitly. The quality of new RESC-AIMP has been tested by calculating the spectroscopic properties of the ...
Recent successes in ab initio calculations of light nuclei (A=2-6) will be reviewed and correlated with the dynamical consequences of chiral symmetry. The tractability of nuclear physics evinced by these results is evidence for that symmetry. The relative importance of three-nucleon forces, four-nucleon forces, multi-pion exchanges, and ...
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 correlation contribution to individual ionization ...
The effects of the 4f shell of electrons and the relativity of valence electrons are compared. The effect of 4f shell (lanthanide contraction) is estimated from the numerical Hartree-Fock (HF) calculations of pseudo-atoms corresponding to Hf, Re, Au, Hg, ...
Using the state-of-the-art ab initio electronic structure calculations, we explain why ?-Po prefers the simple cubic structure (it is due to the relativistic mass-velocity and Darwin terms), elucidate its extreme elastic anisotropy (this is an intrinsic property of the simple cubic crystal structure), and predict a transformation to a ...
Recent measurements by Heinzmann, et al., of the spin polarization of photoelectrons ejected from xenon by unpolarized light are in serious disagreement with various theoretical calculations. In this letter we report an ab initio study of spin polarization using the relativistic random-phase approximation (RRPA). Excellent agreement is ...
Multielectron coincidence spectroscopy has been used to study multiple ionization of atomic mercury. The binding energies of triply and quadruply ionized states of Hg have been determined from three- and fourfold electron coincidences. Relativistic ab initio theory has been used to calculate the state energies and predict the ...
It is now possible to calculate many properties including the energetics (total bond dissociation energies or heats of formation) of molecules containing light elements to high accuracy by using correlation-consistent basis sets, coupled cluster theory an...
The shielding of the nuclear magnetic moment by the bound electron in hydrogenlike ions is calculated ab�initio with inclusion of relativistic, nuclear, and quantum electrodynamics (QED) effects. The QED correction is evaluated to all orders in the nuclear binding strength parameter and, independently, to the first order in the expansion in this ...
The shielding of the nuclear magnetic moment by the bound electron in hydrogenlike ions is calculated ab initio with inclusion of relativistic, nuclear, and quantum electrodynamics (QED) effects. The QED correction is evaluated to all orders in the nuclear binding strength parameter and, independently, to the first order in the ...
We report the development of a general order relativistic coupled-cluster (CC) code. Our implementation is based on Kramers-paired molecular spinors, utilizes double group symmetry, and is applicable with the full Dirac-Coulomb and several approximate relativistic Hamiltonians. The available methods include iterative and perturbative single-reference CC ...
We present all-electron relativistic studies of the polarizability properties of the Xe dimer. The studies rely on finite-field calculations of the dimer energies obtained by ab initio methods including electron correlations. An extended set of basis functions is designed in order to ensure a high accuracy of the calculations. ...
... 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
We revive intriguing, yet still unexplained, experimental results of Ehrlich and co-workers [Phys. Rev. Lett. 77, 1334 (1996)10.1103/PhysRevLett.77.1334; Phys. Rev. Lett. 67, 2509 (1991)10.1103/PhysRevLett.67.2509] who have observed, that 5d adatoms distributed on (111) surface islands of 5d metals favor the adsorption at the cluster�s edge rather than at the cluster�s interior, which lies ...
Within the independent particle model we solve the time-dependent single-particle equation using ab initio SCF-DIRAC-FOCK-SLATER wavefunctions as a basis. To reinstate the many-particle aspect of the collision system we use the inclusive probability formalism to answer experimental questions. As an example we show an application to the case of S15+ on Ar ...
Interaction potentials of the iodine atom, atomic cation, and anion with light rare-gas atoms from He to Ar are calculated within the unified ab initio approach using the unrestricted coupled-cluster with singles and doubles and perturbative treatment of triples correlation treatment, relativistic small-core pseudopotential, and an ...
The millimeter-wave rotational spectrum of ethanetellurol has been recorded and assigned for the first time. The spectroscopic study has been complemented by high level ab initio calculations. Geometries, total electronic energies, and harmonic vibrational frequencies have been determined at the MP2 level. A small-core relativistic ...
The factors that need to be taken into account to achieve spectroscopic accuracy for triatomic molecules are considered focusing on H3+ and water as examples. The magnitude of the adiabatic and non-adiabatic corrections to the Born-Oppenheimer approximation is illustrated for both molecules, and methods of including them ab initio are discussed. Electronic ...
The potential energy surface of the ground state of the He-MnH(X (7)Sigma(+)) van der Waals complex is presented. Within the supermolecular approach of intermolecular energy calculations, a grid of ab initio points was computed at the multireference configuration interaction level using the aug-cc-pVQZ basis set for helium and hydrogen and the ...
Within the independent particle model we solve the time---dependent single-particle equation using [ital ab] [ital initio] [ital SCF]-DIRAC-FOCK-SLATER wavefunctions as a basis. To reinstate the many-particle aspect of the collision system we use the inclusive probability formalism to answer experimental questions. As an example we show an application to ...
Extensive ab initio calculations using a complete active space second-order perturbation theory wavefunction, including scalar and spin-orbit relativistic effects with a quadruple-zeta quality basis set were used to construct an analytical potential energy surface (PES) of the ground state of the [H, O, I] system. A total of 5344 ...
Quasirelativistic and nonrelativistic energy adjusted ab initio pseudopotentials for the elements Hg through Rn are presented together with corresponding optimized valence basis sets. Core-valence correlation is accounted for by semiempirical polarization potentials. Corrections to the point charge repulsion in the core-nucleus interaction for subsequent ...
We performed a comprehensive study of the static, dynamic, and electronic properties of liquid Pb at T=650K , ?=0.0309�?3 by means of 216-particle ab initio molecular dynamics simulations based on a real-space implementation of pseudopotentials constructed within density-functional theory. The predicted results and available experimental data are in ...
We present results for a comprehensive study of the static, dynamic and electronic properties of liquid Pb near melting by means of 216-particle ab initio molecular dynamics simulations based on a real-space implementation of pseudopotentials constructed within density-functional theory. The predicted results and available experimental data are in very ...
Following atomic photoionization, the abrupt change in potential can lead to secondary ionization of an outer-shell electron in a phenomenon known as shake-off, a process which gives rise to the asymmetric K? profile and satellite lines. Investigation of chemical effects and relativistic quantum mechanics requires a theoretical determination of these satellite intensities; ...
... 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. ...
... 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 report ab initio correlated relativistic calculations of the effective electric field W{sub d} acting on the electron in two excited electronic states of PbO, required for extracting the electric dipole moment of the electron from an ongoing experiment at Yale, which has the potential of improving accuracy for this elusive property ...
The structure of atomic clusters is investigated using methods of ab initio quantum chemistry in conjunction with scanning tunneling microscopy (STM). Gold sols are imaged via STM and their sizes characterized. Atomic resolution reveals facets, steps, and reconstructed surfaces of the sols. STM images of graphite surfaces are characterized by two ...
The L2,3 x-ray absorption near-edge structures (XANES) and electron energy loss near-edge structures (ELNES) of 3d transition metal (TM) oxides are systematically calculated by the ab initio charge transfer multiplet (CTM) method using fully relativistic molecular spinors on the basis of density-functional theory. The electronic ...
A highly accurate, global dipole moment surface (DMS) is calculated for the water molecule using ab initio quantum chemistry methods. The new surface is named LTP2011 and is based on all-electron, internally contracted multireference configuration interaction, including size-extensivity corrections in the aug-cc-pCV6Z basis set. Dipoles are computed as ...
A refined version of the ''shape consistent'' effective potential procedure of Christiansen, Lee, and Pitzer was used to compute averaged relativistic effective potentials (AREP) and spin--orbit operators for the elements Rb through Xe. Particular attention was given to the partitioning of the core and valence space and, where appropriate, ...
The infinite-order regular approximation (IORA) and IORA with modified metric (IORAmm) is used to develop an algorithm for calculating relativistically corrected isotropic hyperfine structure (HFS) constants. The new method is applied to the calculation of alkali atoms Li-Fr, coinage metal atoms Cu, Ag, and Au, the Hg+ radical ion, and the mercury containing radicals HgH, ...
Atomic Compton profiles (CPs) are a very important property which provide us information about the momentum distribution of atomic electrons. Therefore, for CPs of heavy atoms, relativistic effects are expected to be important, warranting a relativistic treatment of the problem. In this paper, we present an efficient approach aimed at ...
We report on the determination of a high quality ab initiu potential energy surface (PES) and dipole
