scholarly journals High-Accuracy ab Initio Rotation-Vibration Transitions for Water

Science ◽  
2003 ◽  
Vol 299 (5606) ◽  
pp. 539-542 ◽  
Author(s):  
O. L. Polyansky
Keyword(s):  
Ab Initio ◽  
High Accuracy

scholarly journals The Degree of Oxidation of Graphene Oxide

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 560
Author(s):  
Alexandra Carvalho ◽  
Mariana C. F. Costa ◽  
Valeria S. Marangoni ◽  
Pei Rou Ng ◽  
Thi Le Hang Nguyen ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Ab Initio ◽  
State Of The Art ◽  
High Accuracy ◽  
Precise Determination ◽  
Photoemission Spectroscopy ◽  
Pristine Graphene ◽  
X Ray ◽  
Degree Of Oxidation

We show that the degree of oxidation of graphene oxide (GO) can be obtained by using a combination of state-of-the-art ab initio computational modeling and X-ray photoemission spectroscopy (XPS). We show that the shift of the XPS C1s peak relative to pristine graphene, ΔEC1s, can be described with high accuracy by ΔEC1s=A(cO−cl)2+E0, where c0 is the oxygen concentration, A=52.3 eV, cl=0.122, and E0=1.22 eV. Our results demonstrate a precise determination of the oxygen content of GO samples.

High Accuracy ab Initio Calculations on Reactions of OH with 1-Alkenes. The Case of Propene

2009 ◽  
Vol 5 (9) ◽  
pp. 2313-2321 ◽  
Author(s):  
Róbert Izsák ◽  
Milán Szőri ◽  
Peter J. Knowles ◽  
Béla Viskolcz
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
High Accuracy

High-accuracy extrapolated ab initio thermochemistry of the NCN radical

2018 ◽  
Vol 706 ◽  
pp. 613-616 ◽  
Author(s):  
Michael E. Harding ◽  
Matthias Olzmann
Keyword(s):  
Ab Initio ◽  
High Accuracy

scholarly journals High accuracy ab initio studies of Li6+, Li6−, and three isomers of Li6

2005 ◽  
Vol 122 (6) ◽  
pp. 064315 ◽  
Author(s):  
Berhane Temelso ◽  
C. David Sherrill
Keyword(s):  
Ab Initio ◽  
High Accuracy

High-Accuracy Extrapolated Ab Initio Thermochemistry of Vinyl Chloride

2007 ◽  
Vol 111 (51) ◽  
pp. 13623-13628 ◽  
Author(s):  
Michael E. Harding ◽  
Jürgen Gauss ◽  
Klaus Pflüger ◽  
Hans-Joachim Werner
Keyword(s):  
Ab Initio ◽  
Vinyl Chloride ◽  
High Accuracy

scholarly journals High-Accuracy Extrapolated Ab Initio Thermochemistry of Vinyl Chloride

2008 ◽  
Vol 112 (22) ◽  
pp. 5024-5024 ◽  
Author(s):  
Michael E. Harding ◽  
Jürgen Gauss ◽  
Klaus Pflüger ◽  
Hans-Joachim Werner
Keyword(s):  
Ab Initio ◽  
Vinyl Chloride ◽  
High Accuracy

scholarly journals SPECTROSCOPIC AND THERMOCHEMICAL PROPERTIES OF ACTINIDE-CONTAINING SPECIES FROM FIRST PRINCIPLES: THORIUM AND AMERICIUM MONOXIDE MOLECULES

2020 ◽  
Vol 63 (2) ◽  
pp. 4-13
Author(s):  
Alexander N. Smirnov ◽  
Victor G. N. Solomonik
Keyword(s):  
Ab Initio ◽  
Bond Length ◽  
Molecular Spectroscopy ◽  
High Accuracy ◽  
Ionization Potentials ◽  
Minor Actinide ◽  
Accuracy Evaluation ◽  
Molecular Constants ◽  
Full Account ◽  
Calculation Results

A relativistic version of a composite ab initio treatment of molecular spectroscopy and thermochemistry is developed, focusing on high-accuracy description of the properties of actinide (An) containing species. It is based on combining the calculation results at levels of theory with sufficiently full account of electron correlation, e.g., at the CCSDT(Q) level, but tackling only scalar relativity, with those obtained from more rigorous four-component relativistic calculations with the Dirac–Coulomb Hamiltonian. High accuracy achievable via this approach is revealed taking the examples of thorium and americium monoxide molecules. The errors in ab initio values for the bond length re, vibrational frequency ωe, and atomization energy D0 of the ThO molecule did not exceed 0.001 Å, 2.5 cm–1, and 0.5 kcal/mol, respectively. The composite numerical values for the first ionization potentials of the AmO molecule and the Am atom deviate from the experimental data just by 0.03 eV and 1 cm–1, respectively. For the first time, the proposed approach enabled high-accuracy evaluation of the molecular constants re, ωe and D0 for AmO and AmO+, as well as the second and third ionization potentials of the Am atom. The calculation results are indicative of a minor actinide contraction of the An–O bonds on going through the molecular series ThO → UO → AmO: the bond length in AmO is by 0.0073 Å shorter than that in ThO. The re(An–O) value is shown to be linearly dependent on the actinide atomic number in the periodic table. The results obtained may be used as benchmarks for parametrizing and calibrating the DFT functionals designed for treating An-containing molecules.

scholarly journals Accelerated Modeling of Lithium Diffusion in Solid State Electrolytes Using Artificial Neural Networks

2020 ◽  
Author(s):  
Karun Kumar Rao ◽  
Yan Yao ◽  
Lars Grabow
Keyword(s):  
Neural Networks ◽  
Molecular Dynamics ◽  
Artificial Neural Networks ◽  
Solid State ◽  
Ab Initio ◽  
Density Functional ◽  
Lithium Ion ◽  
Md Simulations ◽  
High Accuracy ◽  
Artificial Neural

There is great interest in solid state lithium electrolytes to replace the flammable organic electrolyte for an all solid state battery. Previous efforts trying to understand the structure-function relationships resulting in high ionic conductivity materials have mainly relied on <i>ab initio</i> molecular dynamics. Such simulations, however, are computationally demanding and cannot be reasonably applied to large systems containing more than a few hundred atoms. Herein, we investigate using artificial neural networks (ANN) to accelerate the calculation of high accuracy atomic forces and energies used during molecular dynamics (MD) simulations, to eliminate the need for costly <i>ab initio </i>force and energy evaluation methods, such as density functional theory (DFT). After carefully training a robust ANN for four and five element systems, we obtain nearly identical lithium ion diffusivities for Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> (LGPS) when benchmarking the ANN-MD results with DFT-MD. To demonstrate the power of the outlined ANN-MD approach we apply it to a doped LGPS system to calculate the effect of concentrations of chlorine on the lithium diffusivity at a resolution that would be unrealistic to model with DFT-MD. We find that ANN-MD simulations can provide the framework to study systems that require a large number of atoms more efficiently while maintaining high accuracy.

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