Results 241 to 250 of about 7,871,511 (280)

Theoretical 0–0 Energies with Chemical Accuracy

The Journal of Physical Chemistry Letters, 2018
Ab initio calculation of electronic excitation energies with chemical accuracy (ca. 1 kcal·mol-1 or 0.043 eV with respect to experiment) is a long-standing challenge in electronic structure theory. Indeed, the most advanced theories can, in practice, only be used to estimate vertical transition energies that cannot be measured experimentally, whereas ...
Pierre-François Loos, Nicolas Galland, Denis Jacquemin   +2 more
openaire   +3 more sources

The accuracy of Kramers' theory of chemical kinetics

Physica A: Statistical Mechanics and its Applications, 1979
Abstract The diffusive escape rate out of a potential well is studied. Kramers' original method is compared with the result of an eigenfunction analysis of the Smoluchowski equation for diffusion in a double well potential. It is shown that by evaluating exactly two integrals, calculated by Kramers in a gaussian approximation, the relative error will
O. Edholm, O. Leimar
openaire   +1 more source

Calibration Accuracy of Chemical Injection Devices

Applied Engineering in Agriculture, 1996
Chemigation has become an accepted chemical application method, but insufficient data document that actual chemical injection rates fall within acceptable limits of the manufacturer’s rated capacity. Piston, diaphragm, and venturi type injection devices were tested to establish their linearity, repeatability, and steady-state accuracy for a series of ...
null W. L. Kranz, null D. E. Eisenhauer, null A. M. Parkhurst   +2 more
openaire   +1 more source

Confined Chemical Etching for Electrochemical Machining with Nanoscale Accuracy

Accounts of Chemical Research, 2016
In the past several decades, electrochemical machining (ECM) has enjoyed the reputation of a powerful technique in the manufacturing industry. Conventional ECM methods can be classified as electrolytic machining and electroforming: the former is based on anodic dissolution and the latter is based on cathodic deposition of metallic materials. Strikingly,
Dongping, Zhan, Lianhuan, Han, Jie, Zhang, Kang, Shi, Jian-Zhang, Zhou, Zhao-Wu, Tian, Zhong-Qun, Tian   +6 more
openaire   +2 more sources

A priori calculation of molecular properties to chemical accuracy

Journal of Physical Organic Chemistry, 2004
AbstractQuantum chemical methods for the calculation of molecular properties to chemical accuracy are reviewed. We begin by reviewing wave‐function based electronic structure theory, with emphasis on coupled‐cluster theory and the description of electron correlation in terms of virtual excitations from occupied to virtual molecular orbitals.
Helgaker, Trygve, Ruden, Torgeir A., Jørgensen, Poul, Olsen, Jeppe, Klopper, Wim   +4 more
openaire   +3 more sources

Accuracy of the chemical-pseudopotential method for tetrahedral semiconductors

Physical Review B, 1993
Simple two-center tight-binding models have often been used in electronic-structure calculations, although uncertainty about the foundations of the tight-binding method has severely limited progress. This uncertainty has been much reduced following the recent successes of the non-self-consistent Harris scheme but several important questions still ...
openaire   +3 more sources

Beyond Chemical Accuracy for Alkane Thermochemistry: The DHthermo Approach

The Journal of Organic Chemistry, 2021
The so-called protobranching phenomenon, that is the greater stability of branched alkanes with respect to their linear isomers, represents an interesting challenge for approaches based on density functional theory (DFT), since it requires a balanced description of several electronic effects, including (intramolecular) dispersion forces.
Hanwei Li, Bernardino Tirri, Eric Brémond, Juan Carlos Sancho-García, Carlo Adamo   +4 more
openaire   +2 more sources

Simulation of Chemical Application Accuracy for Injection Sprayers

Transactions of the ASAE, 1992
Theoretical chemical application rates were derived for injection sprayers with a constant flow rate of spray mixture and a spray mixture concentration proportional to ground speed. Computer simulations were developed to predict chemical application accuracies for injection sprayers accelerating at 1.6 km/h/s from rest to constant speed.
null T. R. Way, null K. Von Bargen, null R. D. Grisso, null L. L. Bashford   +3 more
openaire   +1 more source

On the accuracy of a localised description of chemical bonding

Journal of Molecular Structure: THEOCHEM, 1982
Abstract The applicability and accuracy of a localised picture of chemical bonding is examined on the basis of the projection approach to orbital localisation. The condition for maximal localisation is chosen to minimize the fluctuation in a number of electrons per bond.
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Evaluation of the Accuracy of Selected Syngas Chemical Mechanisms

Journal of Energy Resources Technology, 2015
The implementation of reduced syngas combustion mechanisms in numerical combustion studies has become inevitable in order to reduce the computational cost without compromising the predictions' accuracy. In this regard, the present study evaluates the predictive capabilities of selected detailed, reduced, and global syngas chemical mechanisms by ...
Alzahrani, F. M., Sanusi, Y. S., Vogiatzaki, K., Ghoniem, A. F., Habib, M. A., Mokheimer, E. M. A.   +5 more
openaire   +2 more sources