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Showing 1 to 15 of 15 for “"Ab initio calculation"”.
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Organoisocyanates: the conformational stability determination by infrared, raman and microwave spectroscopy and ab initio calculation
Conformational stability studies have been carried out for several quasilinear organoisocyanates and organoisothiocyanates. The infrared and Raman spectra in the gaseous, liquid and solid phases have been recorded as well as the variable temperature infrared spectra of the sample compound dissolved …
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New perspectives on ab initio calculation and physical insights gained through linkage to continuum theories
We explore the use of ab initio, density-functional methods for the study of large-scale materials problems. Three examples are presented: (i) the interplay of surface and edge reconstructions in long silicon nanowires, where we examine the effects on electrical and mechanical properties; (ii) the …
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The Ab Initio Calculation of the Chemical Shift Tensor and its Application for the Structure Determination in Ordered and Disordered Phases by Means of Solid-State Nuclear Magnetic Resonance
… Besides structural modelling this included the ab initio calculation of the chemical shift tensor which was taken for the simulation of various solid-state NMR experiments and the comparison to NMR measurements. In this context it was necessary to create a tool which could deal with the analysis …
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Multiscale ab initio approaches to materials physics
This work presents new ab initio approaches to materials physics. We first introduce the multiscale approach to determination of thermal properties and changes in free energy. With this approach one can perform thermal averaging of ensembles of states with ab initio methods, thus enabling ab initio …
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Design Of Functional Dendrimer Nanocarriers And Their Formulations In Propellant-Based Inhalers For Pulmonary Drug Delivery
… design biocompatible moieties for the steric stabilization of suspension formulations in HFO-based propellants. Using a combination of tools including ab initio calculation, molecular dynamics simulation and high pressure tensiometry, potential fluorocarbon-philic moieties were systematically …
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Effects of Anion Excited States on Photodetachment of Negative Ions
… or electronic autodetachment) is explored using ab initio calculation. EOM-CCSD calculation reveals a dipole bound anion state, which is responsible for vibrational autodetachment observed in AgF<super>-</super> detachment. Additionally, CAP/EOM-CCSD calculation and experimental data suggest the …
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Theoretical study of carbon nanotubes adsorbed on the silicon (100) surface and explorations on the modulation of conductance for metallic carbon nanotubes
We present the first ab initio study of semiconducting carbon nanotubes adsorbed on the unpassivated Si(100) surface. A dramatic reduction of the semiconducting gap for these hybrid systems as compared with the electronic gaps of their isolated constitutive components was found. This is caused by …
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A study of carbon and iron charged point defects in gallium nitride: electronic structure implications for high-power photoconductive solid state switch applications
… results have not been obtained. Therefore, the ability to determine those parameters via ab initio calcula- tions is essential, especially when the material contains some type of defect or dopant. To overcomes this dilemma, we proposed a simulation methodology to ex- tract the needed parameters …
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An empirical potential for hydrogen bond energies determination of the orientation of anthracene molecules in the unit cell by means of a refractivity method: some ab initio calculations involving acetonitrile exchange reaction
… between the empirical potential and the ab initio results of 216 configurations of (H₂O)₂, (NH₃)₂ and NH₃•H₂O is 0.9 kcal/mol and 0.5 kcal/mol for 61 configurations of methanol dimers. Applications of the potential to water dimers, ammonia dimers, their mixed dimers, water oligomers and …
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An advanced perspective on twin growth in nickel-titanium
… is investigated. Density Functional Theory based ab initio calculation and Molecular dynamics (MD) correspond to the right length and time scale for these events, and utilized in this study. The first part of the work elucidates the details of twinning in martensite (B19’) and austenite (B2) as …
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Exploration of basis set issues for calculation of intermolecular interactions and density functional theory calculations of vanadium oxide clusters and their reactions with sulfur dioxide
The ab initio calculation of intermolecular interactions requires a large basis set in order to describe systems with dominant dispersion interaction accurately. This work focuses on calculation of intermolecular bonding energies of weakly bound systems within the supermolecular method and on …
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Potential Energy Surface around the Tropylium Ion.
… feasible at a fairly high level of theory. The calculations that we performed were at the HF/6-31G (d, p) and the B3LYP/6-311++G (2d) levels. This work will show areas of the potential energy surface around the highly symmetric tropylium ion to give a glance of possible mechanisms for its …
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Theoretical Study on the Mechanism of Removing Nitrogen Oxides using Isocyanic Acid.
… have been evaluated and the chemically reasonable ones have been considered to propose new sets of reaction mechanisms. Density Functional Theory (B3LYP/6-31 G**) calculations using Gaussian 98<sup>3</sup> were made in order to study the relative energies of all species and to predict the …
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Development and Implementation of Theoretical Methods for the Calculation of EPR Parameters in Periodic Simulations
… only on the fundamental laws of quantum physics (ab initio), has been a very active and valuable field of research. Density functional theory (DFT) is a particularly successful ab-initio technique, which was developed by Hohenberg and Kohn, and formulated into a useful algorithm by Kohn and Sham. …
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Lattice to continuum: A theoretical framework to calculate elastic fields in lattice scale
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01