Results 261 to 270 of about 6,717,903 (305)
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A comparison of polarization and bond functions for density functional calculations
Molecular Physics, 2004The basis set convergence of density functional calculations is analyzed by comparing nuclear centred polarization functions with bond functions placed at the bond midpoints, and combinations of these two. The H2, N2 and N4 systems are analyzed by explicit optimization of the exponents of the polarization and bond functions.
Bruun, J., Helgaker, T., Jensen, Frank
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The Journal of Physical Chemistry A, 2007
Recently, two computational approaches that supply a density-functional-based quantum-chemical method with an empirical term accounting for London dispersion were introduced and found use in the studies of biomolecular systems, namely, DFT-D and SCC-DFTB-D.
Tomas, Kubar +6 more
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Recently, two computational approaches that supply a density-functional-based quantum-chemical method with an empirical term accounting for London dispersion were introduced and found use in the studies of biomolecular systems, namely, DFT-D and SCC-DFTB-D.
Tomas, Kubar +6 more
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Density Functional Calculation of Intermolecular Potentials
The Journal of Physical Chemistry A, 2011Calculations of intermolecular potentials following the density functional theory (DFT) turn out to be very complicated without using some appropriate approximations. Most often the following three approximations have been considered. In one approximation the disturbed charge distributions during collisions are reduced to sums of undisturbed charge ...
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Calculation of Doppler spectral power density functions
IEEE Transactions on Biomedical Engineering, 1992A volume integral method for the calculation of Doppler ultrasound spectral power density (spd) functions is described. Axisymmetric flow in a circular tube with a power law velocity profile is assumed. The spd function is regarded as a probability density function for scatterer velocity, and the assumptions under which this is justified are considered.
Gepffrey K. Aldis, Rosemary S. Thompson
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Calculation of nonadiabatic couplings in density-functional theory
The Journal of Chemical Physics, 2004This paper proposes methods for calculating the derivative couplings between adiabatic states in density-functional theory (DFT) and compares them with each other and with multiconfigurational self-consistent field calculations. They are shown to be accurate and, as expected, the costs of their calculation scale more favorably with system size than ...
Salomon R, Billeter, Alessandro, Curioni
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Direct calculation of electron density in density-functional theory
Physical Review Letters, 1991A new approach for the study of ground states of many-electron systems is developed via direct calculation of the density in density-functional theory. Not using the Kohn-Sham equations, the method divides a system into subsystems in physical space and determines the density for each subsystem.
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Density Functional Calculation for BP/GaN Heterostructures
Materials Science Forum, 2018Recently, it has become indispensable to use semiconducting nanostructures in the production and development of electronic devices. In this study, the bulk and nanowire heterostructures of the BP / GaN system have been investigated for the structures pure and Te atom doped.
Özkişi H., Dalgıç S.
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Density Functional Calculations
2010Density functional theory is based on the two Hohenberg-Kohn theorems, which state that the ground-state properties of an atom or molecule are determined by its electron density function, and that a trial electron density must give an energy greater than or equal to the true energy (the latter theorem is true only if the exact functional could be used).
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Density Functional Calculations Based on the Exponential Ansatz
The Journal of Physical Chemistry A, 2021This work explores the application of the singles-based exponential ansatz to density functional calculations. In contrast to the standard approach where Kohn-Sham (KS) orbitals are determined prior to computing molecular quantities of interest, we consider the single-reference Hartree-Fock wave function as a starting point.
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Density functional calculations of surface free energies
The Journal of Chemical Physics, 2006We propose a general method of thermodynamic integration to find the free energy of a surface, where our integration parameter is taken to be the strain on the unit cell of the system (which in the example presented in this paper is simply the extension of the unit cell along the normal to the surface), and the integration is performed over the thermal
H, Fox, A P, Horsfield, M J, Gillan
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