Density functional theory with approximate kinetic energy functionals applied to hydrogen bonds

1997 ◽  
Vol 106 (20) ◽  
pp. 8516-8526 ◽  
Author(s):  
Tomasz Adam Wesolowski
Keyword(s):  
Density Functional Theory ◽  
Kinetic Energy ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Functional Theory ◽  
Energy Functionals

Development of novel kinetic energy functional for orbital-free density functional theory applications

2021 ◽  
Author(s):  
Vittoria Urso
Keyword(s):  
Density Functional Theory ◽  
Energy Density ◽  
Kinetic Energy ◽  
Density Functional ◽  
Energy Functional ◽  
Kinetic Energy Density ◽  
Functional Theory ◽  
Energy Functionals ◽  
Kinetic Energy Functional ◽  
Orbital Free

The development of novel Kinetic Energy (KE) functionals is an important topic in density functional theory (DFT). In particular, this happens by means of an analysis with newly developed benchmark sets. Here, I present a study of Laplacian-level kinetic energy functionals applied to metallic nanosystems. The nanoparticles are modeled using jellium sph eres of different sizes, background densities, and number of electrons. The ability of different functionals to reproduce the correct kinetic energy density and potential of various nanoparticles is investigated and analyzed in terms of semilocal descriptors. Most semilocal KE functionals are based on modifications of the second-order gradient expansion GE2 or GE4. I find that the Laplacian contribute is fundamental for the description of the energy and the potential of nanoparticles.

Approximate kinetic energy density functionals generated by local-scaling transformations

1996 ◽  
Vol 74 (6) ◽  
pp. 1097-1105 ◽  
Author(s):  
E.V. Ludeña ◽  
R. López-Boada ◽  
R. Pino
Keyword(s):  
Density Functional Theory ◽  
Energy Density ◽  
Kinetic Energy ◽  
Density Functional ◽  
Kinetic Energy Density ◽  
Density Functionals ◽  
Functional Theory ◽  
Local Scaling ◽  
Energy Functionals ◽  
Key Words Density

Different stages in the development of density functional theory are succinctly reviewed for the purpose of tracing the origin of the local-scaling transformation version of density functional theory. Explicit kinetic energy functionals are generated within this theory. These functionals are analyzed in terms of several approximations to the local-scaling function and are applied to a few selected first-row atoms. Key words: density functional theory, kinetic energy density functionals, local-scaling transformations, explicit kinetic energy functionals, kinetic energy of first-row atoms.

scholarly journals Spectroscopic, X-ray Diffraction and Density Functional Theory Study of Intra- and Intermolecular Hydrogen Bonds in Ortho-(4-tolylsulfonamido)benzamides

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 926
Author(s):  
Malose J. Mphahlele ◽  
Eugene E. Onwu ◽  
Marole M. Maluleka
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Tetrahedral Geometry ◽  
Hindered Rotation ◽  
Hydrogen Bond Acceptor ◽  
Functional Theory ◽  
Vis Spectroscopy ◽  
Hydrogen Bonded

The conformations of the title compounds were determined in solution (NMR and UV-Vis spectroscopy) and in the solid state (FT-IR and XRD), complemented with density functional theory (DFT) in the gas phase. The nonequivalence of the amide protons of these compounds due to the hindered rotation of the C(O)–NH2 single bond resulted in two distinct resonances of different chemical shift values in the aromatic region of their 1H-NMR spectra. Intramolecular hydrogen bonding interactions between the carbonyl oxygen and the sulfonamide hydrogen atom were observed in the solution phase and solid state. XRD confirmed the ability of the amide moiety of this class of compounds to function as a hydrogen bond acceptor to form a six-membered hydrogen bonded ring and a donor simultaneously to form intermolecular hydrogen bonded complexes of the type N–H···O=S. The distorted tetrahedral geometry of the sulfur atom resulted in a deviation of the sulfonamide moiety from co-planarity of the anthranilamide scaffold, and this geometry enabled oxygen atoms to form hydrogen bonds in higher dimensions.

6-Bromoindigo dye

2012 ◽  
Vol 68 (4) ◽  
pp. o160-o163 ◽  
Author(s):  
David J. Szalda ◽  
Keith Ramig ◽  
Olga Lavinda ◽  
Zvi C. Koren ◽  
Lou Massa
Keyword(s):  
Density Functional Theory ◽  
Quantum Theory ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Stacking Interactions ◽  
Inversion Center ◽  
Asymmetric Unit ◽  
Functional Theory ◽  
Bond Lengths ◽  
Type C

6-Bromoindigo (MBI) [systematic name: 6-bromo-2-(3-oxo-2,3-dihydro-1H-indol-2-ylidene)-2,3-dihydro-1H-indol-3-one], C16H9BrN2O2, crystallizes with one disordered molecule in the asymmetric unit about a pseudo-inversion center, as shown by the Br-atom disorder of 0.682 (3):0.318 (3). The 18 indigo ring atoms occupy two sites which are displaced by 0.34 Å from each other as a result of this packing disorder. This difference in occupancy factors results in each atom in the reported model used to represent the two disordered sites being 0.08 Å from the higher-occupancy site and 0.26 Å from the lower-occupancy site. Thus, as a result of the disorder, the C—Br bond lengths in the disordered components are 0.08 and 0.26 Å shorter than those found in 6,6′-dibromoindigo (DBI) [Süsse & Krampe (1979).Naturwissenschaften,66, 110], although the distances within the indigo ring are similar to those found in DBI. The crystals are also twinned by merohedry. Stacking interactions and hydrogen bonds are similar to those found in the structures of indigo and DBI. In MBI, an interaction of the type C—Br...C replaces the C—Br...Br interactions found in DBI. The interactions in MBI were calculated quantum mechanically using density functional theory and the quantum theory of atoms in molecules.

Sign in / Sign up

Export Citation Format

Share Document