Density functional theory nonlocal corrections

Density functional theory, 21, 31, 245-246 B3LYP functional, 246 Hartree-Fock-Slater exchange, 246 Kohn-Sham equations, 245 local density approximation, 246 nonlocal corrections, 246 Density matrix, 232 Determinantal wave function, 23 Dewar benzene, 290 from acetylene + cyclobutadiene, 290 interaction diagram, 297 rearrangement to benzene, 290, 296-297 DFT, see Density functional theory... 

Tel. 612-683-3688, fax 612-683-3099, e-mail mcole cray.com DGauss for density functional theory calculations with nonlocal, SCF corrections, and geometry optimization. Cadpac 5.0 for ab initio calculations. MNDO90 for semiempirical molecular orbital calculations. A package with a graphics front end for structure input and visualizations of electron density, electrostatic potentials, and molecular orbitals. Silicon Graphics and Macintosh (under X-Windows) networked to a Cray. 

Density Functional theory [4] (DFT) has been widely recognized as a powerful alternative computational method to traditional ab initio schemes, particularly in studies of transition metal complexes where large size of basis set and an explicit treatment of electron correlation are required. The local spin density approximation [5] (LDA) is the most frequently applied approach within the families of approximate DFT schemes. It has been used extensively in studies on solids and molecules. Most properties obtained by the LDA scheme are in better agreement with experiments [4a] than data estimated by ab initio calculations at the Hartree-Fock level. However, bond energies are usually overestimated by LDA. Thus, gradient or nonlocal corrections [6] have been introduced to rectify the shortcomings in the LDA. The non-... 

Density functional theory, 21, 31, 245-246 B3LYP functional, 246 Hartree-Fock-Slater exchange, 246 Kohn-Sham equations, 245 local density approximation, 246 nonlocal corrections, 246... 

Relativistic density functional theory, especially with the inclusion of nonlocal exchange and correlation corrections, has become a powerful predictive tool in actinide chemistry. The methodology is sufficiently efficient to allow experimentally important properties, such as the geometry, vibrational frequencies, and infrared absorption intensities, to be calculated even for large organoactinide systems such as those discussed here. Inasmuch as many aspects of actinide chemistry are experimentally challenging because of the difficulty in handling of the elements, reliable theoretical calculations provide a valuable adjunct to experimental studies. 

Density functional theory calculations require a density functional. By now, a very large number of functionals have been introduced into the literature. The earliest were so-called local functionals. Subsequently, so-called nonlocal functionals were developed, otherwise known as gradient-corrected functionals. Most recently, a class of functionals referred to as hybrid functionals have been developed [16]. At the present time, hybrid functionals are the most accurate functionals available for a wide range of properties. The earliest hybrid functional is known as B3PW91 [16]. A very popular hybrid functional is B3LYP [17]. 

Several articles on corrections of van der Waals interactions applying the seamless approach in density functional theory have appeared in the literature [47-50]. In an early article of a series, Dion et al. developed and applied a van der Waals density functional in order to treat situations for which nonlocal, long-ranged interactions, such as van der Waals (vdW) forces, were influential. The authors suggested the following form ... 

The ab initio calculations are performed for the above clusters based on the density functional theory(DFT) with the local density approxima-tion(LDA) using the deMon programme . As indicted by Philipsen, Velde and Baerends that, in the case of chemisorption of CO on Cu, while including the nonlocal corrections is essential in order to obtain the chemisorption energy to fair accuracy, it has no much influence on the calculated structure and vibrational frequencies. The DZVP basis sets are used for the C, 0 and Cu atoms in the all-electron calculations. 

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