(either ab initio methods or basis sets) for electronic structure calculations, and a graph theory procedure for identifying instantaneous molecular fragment identities...
Science.gov Websites
A systematic method for approximating the ab initio electronic energy of crystal lattices has been improved by the incorporation of long range electrostatic and dispersion interactions. The effect of these long range interactions on the optimization of the crystal structure is reported. The harmonic lattice dynamics have been evaluated to give phonon ...
PubMed
NASA Astrophysics Data System (ADS)
Ab initio molecular orbital calculations of various fragments of the DNA backbone have been performed to aid our understanding of charge localization and transfer following DNA irradiation. Koopmans ionization potentials of H[sub 3]PO[sub 4], H[sub 2]PO[sub 4][sup [minus
Energy Citations Database
Electronic properties have an important role in the metabolism of benzo(a)pyrene (BP) and the mutagenic action of its metabolites. In this paper, the ground electronic state of BP is characterized by the ab initio molecular fragment floating spherical Gaussian orbital method, and a speculative structural-electronic mechanism is ...
... This study involves: Ab-initio crystal orbitals and polymer orbitals; Ab-initio coupled cluster program; Ab-initio quantum chemical calculations and ...
DTIC Science & Technology
... 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
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
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 ...
We study the origins of high-temperature ferromagnetic behavior in graphite by means of unbiased ab-initio calculations and compare them with our data. The experimental results show that oxygen/sulfur-induced edges of graphitic fragments (via unzipping effect) play an essential role in this phenomenon, and that the finite magnetic moment appears if edges ...
... 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,. ...
... Title : AB Initio Study of the Electronic Magnetic Circular Dichroism ... functions are determined using as initio quantum chemical techniques including ...
We report full ab initio Hartree-Fock calculation to compute quantum mechanical interaction energies for ?-trypsin/benzamidine binding complex. In this study, the full quantum mechanical ab initio energy calculation for the entire protein complex with 3238 atoms is made possible by using a recently developed MFCC ...
Due to recent advances in methods and computers, the accuracy of ab calculations has reached a point
NASA Technical Reports Server (NTRS)
We present a new linear scaling ab initio total energy electronic structure calculation method based on the divide-and-conquer strategy. This method is simple to implement, easily to parallelize, and produces very accurate results when compared with the direct ab initio method. The method has been tested using up ...
Glyoxal photodissociation. An ab initio direct classical trajectory study of C2H2O2\\H2�2CO Xiaosong of glyoxal via a three-body fragmentation channel has been studied by direct classical trajectory Institute of Physics. DOI: 10.1063/1.1369153 INTRODUCTION The photofragmentation of glyoxal, C2H2O2
A formula to calculate the charge penetration energy that results when two charge densities overlap has been derived for molecules described by an effective fragment potential (EFP). The method has been compared with the ab initio charge penetration, taken to be the difference between the electrostatic energy from a Morokuma analysis ...
We present a new linearly scaling three-dimensional fragment (LS3DF) method for large scale ab initio electronic structure calculations. LS3DF is based on a divide-and-conquer approach, which incorporates a novel patching scheme that effectively cancels o...
National Technical Information Service (NTIS)
The Linearly Scaling three-dimensional fragment (LS3DF) method is an O(N) ab initio electronic structure method for large-scale nano material simulations. It is a divide-and-conquer approach with a novel patching scheme that effectively cancels out the ar...
In this work, we show that our energy based fragmentation method (Bettens, R. P. A.; Lee, A. M. J. Phys. Chem. A 2006, 110, 8777) accurately reproduces the electrostatic potential for a selection of peptides, both charged and uncharged, and other molecules of biological interest at the solvent accessible surface and beyond when compared with the full ab ...
The study of Highly Charged Ion-induced diatomic (CO) and triatomic (CO2) molecules fragmentation by the coincident measurement of the fragment momenta is presented. It is shown that the experimental results together with ab initio calculations including a large number of potential energy curves evidence the ...
Charge transfer in collisions of carbon ions on a thymine target has been studied theoretically in a wide collision range by means of ab initio quantum chemistry molecular methods. The process appears markedly anisotropic in the whole energy domain, significantly favoured in the perpendicular orientation. A specific decrease of the charge transfer cross ...
This paper introduces the 'Quantum Isostere Database' (QID), a Web-based tool designed to find bioisosteric fragment replacements for lead optimization using stored ab initio data. A wide range of original geometric, electronic, and calculated physical properties are stored for each fragment. Physical descriptors ...
... 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
Fragmentation of the pyridine ring upon K-shell excitation/ionization has been studied with gaseous 2-, 3- and 4-methylpyridine by the electron-impact method. Ab initio molecular orbital (MO) calculations were also carried out to explore electronic states correlating with specific fragments. Some specific ...
The dynamical origins of product state distributions in the unimolecular dissociation of S{sub 0} ketene, CH{sub 2}CO ({tilde X}{sup 1}A{sub 1}) {yields} CH{sub 2}({tilde a} {sup 1}A{sub 1}) + CO, are studied with ab initio molecular dynamics. We focus on rotational distributions associated with ground vibrational state fragments. ...
... 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 ...
EGPred is a Web-based server that combines ab initio methods and similarity searches to predict genes, particularly exon regions, with high accuracy. The EGPred program proceeds in the following steps: (1) an initial BLASTX search of genomic sequence against the RefSeq database is used to identify protein hits with an E-value <1; (2) a second BLASTX ...
PubMed Central
We present a general method for tracking molecular relaxation along different pathways from an excited state down to the ground state. We follow the excited state dynamics of cytosine pumped near the S0-S1 resonance using ultrafast laser pulses in the deep ultraviolet and probed with strong field near infrared pulses which ionize and dissociate the molecules. The fragment ions ...
There are many large-scale nanoscience problems that require ab initio accuracy total energy calculations and atomic relaxations. Unfortunately, the traditional direct ab initio method scales as O(N^3), where N is the number of atoms in the system, and most of the O(N) methods studied in the last decade have ...
We present a general method for tracking molecular relaxation along different pathways from an excited state down to the ground state. We follow the excited state dynamics of cytosine pumped near the S(0)-S(1) resonance using ultrafast laser pulses in the deep ultraviolet and probed with strong field near infrared pulses which ionize and dissociate the molecules. The fragment ...
We present an overview of the energy functions used in two Anisotropic Polarizable Molecular Mechanics (APMM) procedures namely SIBFA (Sum of Interactions Between Fragments Ab initio computed) and GEM (Gaussian Electrostatic Model). As SIBFA is a second generation APMM scheme based on distributed multipoles, GEM is the first third ...
We present refinements of the SIBFA molecular mechanics procedure to represent the intermolecular interaction energies of Zn(II). The two first-order contributions, electrostatic (E(MTP)), and short-range repulsion (E(rep)), are refined following the recent developments due to Piquemal et al. (Piquemal et al. J Phys Chem A 2003, 107, 9800; and Piquemal et al., submitted). Thus, E(MTP) is augmented ...
We report on the determination of a high quality ab initiu potential energy surface (PES) and dipole
The aim of this thesis is to study metallic sodium clusters by numerical simulation. We have developed two ab initio molecular dynamics programs within the formalism of density functional theory. The first is based on the semi- classical extended Thomas-F...
Experimental studies of a photoinitiated collision in an ultracold Cs Rydberg gas are presented. The process is characterized by measuring the laser intensity dependence of the absorption, the number of particles leaving each collision, and the recoil velocity of the collision fragments. The results of the experiment are compared to ab ...
The dynamics of the ethylene molecule in femtosecond laser pulses is studied as a function of the laser parameters using an ab initio time-dependent approach, called nonadiabatic quantum molecular dynamics. We predict that, by choosing different femtosecond pulses with well-defined excitation frequencies, one can selectively induce either the isomerization ...
is a homolysis. When one fragment retains both electrons, the cleavage is a heterolysis. Application into ionized phenol and neutral propene. Ab initio calculations indicate that the neutral ether has two stable for monoenergetic ions,23 but the general applicability to ions with a distribution of internal energies has been
Organosulfur molecules will be investigated by photoionization techniques in order to accurately determine the heats of formation of organosulfur ions and fragments. The structures will be determined by ab initio molecular-orbital calculations. A consider...
In sharp contrast to molecules, electronic states of clusters with an excited intermediate-shell electron can efficiently decay via an intermolecular Coulombic mechanism. Explicit examples are presented using large scale {ital ab initio} propagator calculations. The mechanism is illustrated and its generality is stressed. {copyright} {ital 1997} {ital The ...
recently developed the Rosetta algorithm for ab initio protein structure prediction, which generates protein structures from fragment libraries using simulated annealing. The scoring function sheet motifs. After generat- ing many structures using Rosetta, we found that the folding algorithm
in Rosetta. Selection of fragments to include in the library does, of necessity, use only the localDe Novo Determination of Protein Backbone Structure from Residual Dipolar Couplings Using Rosetta into Rosetta, an ab initio structure prediction method, and demonstrate that the combined algorithm provides
chains. ab initio energy-based fragment assembly nucleic acid Rosetta The biological roles of RNA a complementary approach, inspired by the Rosetta low-resolution protein structure prediction method, that seeks tertiary structure prediction inspired by the Rosetta low-resolution protein structure prediction method
Features of the potential energy surface pertinent to the thermal decomposition mechanism of methylenenitramine (CH(sub 2)NNO(sub 2)) are investigated. At issue are the activation energies both for concerted molecular dissociation leading to HCN and HONO ...
Collision experiments and high-level ab initio calculations are used for the first characterization of the neutral, cationic and anionic Si3N cluster molecules. The experimentally observed fragmentation processes are well described by calculated reaction energies of all dissociation channels. In addition, the geometries and harmonic ...
With blooming experimental synthesis of various nanostructures out of many semiconductor materials, there is an urgent need to calculate the electronic structures and optical properties of these nanosystems based on reliable ab initio methods. Unfortunately, due to the O(N^3) scaling of the conventional ab initio ...
