Density-functional calculations

5 Density Functional Calculations. - Hinchliffe et a/.144,145 give the results of static polarizability calculations for ethene, butadiene and hexatriene using 18 

Fuentalba and Reyes149 report DFT calculations on the electric dipole polarizabilities of Li Hw clusters. The variation of the polarizability with the cluster size and also with the isomeric structure is discussed and related to variations in the hardness, which is taken as proportional to the energy gap. 

Menconi et have further examined the theory exchange-correlation functional and discussed applications to the nuclear shielding in CO and H2O. 

Ferraro has used the B3LYP density functional with LAOs to study the nuclear shielding of H and C in some unsymmetric A, A -dipyridyl ureas. He has related the chemical shifts to the conformations of the molecules and the averaging due to rapid internal rotation. 

Ormsby et al. have calculated B chemical shifts in boron clusters using DFT/GIAO methods and interpreted the results in terms of bond rotamers. 

Bagno and Bonehio have ealeulate the nuclear shielding of the tungsten nucleus in mononuclear tungsten eomplexes using DFT with effective core potentials. 

De Proft and Geerlings have reviewed DFT in relation to the study of aromaticity. 

My other hope is that... a basically new ab initio treatment capable of giving chemically accurate results a priori, is achieved soon. 

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Floizwarth N A W, Matthews G E, Dunning R B, Tackett A R and Zeng Y 1997 Comparison of the pro]ector augmented-wave, pseudopotentlal and linearized augmented-plane-wave formalisms for density-functional calculations of solids Phys. Rev. B 55 2005... 

Duarte H A and Salahub D R 1998 Embedded cluster model for chemisorption using density functional calculations oxygen adsorption on the AI(IOO) surface J. Chem. Phys. 108 743... 

Maurits, N.M., Altevogt, P., Evers, O.A., Fraaije, J.G.E.M. Simple numerical quadrature rules for Gaussian Chain polymer density functional calculations in 3D and implementation on parallel platforms. Comput. Theor. Polymer Sci. 6 (1996) 1-8. 

F, St-Amant A, I Papai and D R Salahub 1992. Gaussian Density Functional Calculations on Hydrogen-Bonded Systems, journal of the American Chemical Society 114 4391-4400. ter J C1974. Quantum Theory of Molecules and Solids Volume 4 The Self-Consistent Field for Molecules and Solids. New York, McGraw-Hill. 

Free surface density functions calculated at step 8 are used as the initial conditions to update the current position of the surface using the following integration... 

A number of types of calculations can be performed. These include optimization of geometry, transition structure optimization, frequency calculation, and IRC calculation. It is also possible to compute electronic excited states using the TDDFT method. Solvation effects can be included using the COSMO method. Electric fields and point charges may be included in the calculation. Relativistic density functional calculations can be run using the ZORA method or the Pauli Hamiltonian. The program authors recommend using the ZORA method. 

Table I.IS gives total bonding energies in kilocalories per mole for some simple molecules. The B3iyP results are comparable in accuracy to G1 and G2 results. Another comparison was done with a series of cyclic hydrocarbons as the test case. The calculations were done using an isodesmic reaction scheme. The results are given in Table 1.19. Density functional calculations have also been successfully extended to functionalized molecules. ...

The hetero-Diels-Alder reaction of aldehydes 12 with 2-azabutadienes 13 (Scheme 8.5) has been studied using high-level ab-initio multiconfigurational molecular orbital and density functionality calculation methods [28]. 

Calculations were done with a full-potential version of the LMTO method with nonoverlapping spheres. The contributions from the interstitial region were accounted for by expanding the products of Hankel functions in a series of atom-ce- -ered Hankels of three different kinetic energies. The corrected tetrahedron method was used for Brillouin zone integration. Electronic exchange and correlation contributions to the total energy were obtained from the local-density functional calculated by Ceperley and Alder " and parametrized by Vosko, Wilk, and Nusair. ... 

Extensive quantum chemical calculations have been reported for sulfur-rich compounds in the past two decades. These calculations were used to investigate molecular structures and spectroscopic properties, as well as to understand the nature chemical bonding and reaction mechanism. Many high-level ab initio calculations were used for interpretation of experimental data and for providing accurate predictions of molecular structures and thermochemical data where no reliable experimental values are available. In recent years, density functional calculations have been extensively tested and used on many first- and second-row compounds. These proven DFT methods look promising for larger systems because for their computational efficiency. 

This isomer was first obtained by density functional calculations R.O. Jones, D. Hohl, Int. J. Quantum Chem. Quantum Chem. Symp. 1990, 110, 4703... 

The molecular structures of the isolated polysulfide monoanions 8 with n=2-9 have been studied by density functional calculations and those of the smaller ions also by ab initio MO calculations. Compared to the neutral 8 molecules the extra electron occupies an antibonding orbital resulting in longer 88 bonds. The species 83 is bent and of C2V symmetry (a=115°) [140, 141]. 84 was calculated to be a planar ion of C2V symmetry (similar to the neutral molecule 84) but the planar C2h structure is only slightly less stable [140, 141]. The most stable isomer of 85 is a chain of Q symmetry sim-... 

Ab initio MO calculations at a high level of theory [28] support the open-chain structure for the ground state of S2O while density functional calculations predicted a cyclic ground-state structure [29]. 

Hartree-Fock as well as density functional calculations on hypothetical cyclic oligomers (SO) with =2-4 have been published [56] these species are all more stable than the corresponding number of monomeric SO mole-... 

The local density approximation is highly successful and has been used in density functional calculations for many years now. There were several difficulties in implementing better approximations, but in 1991 Perdew et al. successfully parametrised a potential known as the generalised gradient approximation (GGA) which expresses the exchange and correlation potential as a function of both the local density and its gradient ... 

Figure 6.26. Density functional calculations show the change in the density of states induced by adsorption of Cl, Si and Li on jellium. Lithium charges positively and chlorine negatively. [From N.D. Lang and A.R. Williams,...

Neurock and coworkers [M. Neurock, V. Pallassana and R.A. van Santen, J. Am. Chem. Soc. 122 (2000) 1150] performed density functional calculations for this reaction scheme up to the formation of the ethyl fragment, for a palladium(lll) surface. Figure 6.38(a) shows the potential energy diagram, starting from point at which H atoms are already at the surface. As the diagram shows, ethylene adsorbs in the Jt-bonded mode with a heat adsorption of 30 kj mol and conversion of the latter into the di-a bonded mode stabilizes the molecule by a further 32 kJ mol . ... 

How Much Correlation Can We Expect to Account for in Density Functional Calculations Case Studies of Electrostatic Properties of Small Molecules... 

How much correlation can we expect to account for in density functional calculations Case studies of electrostatic properties of small molecules... 

Anton, J., Ericke, B. and Schwerdtfeger, P. (2005) Non-collinear and collinear four-component relativistic molecular density functional calculations. Chemical Physics, 311, 97-103. 

Han, Y.-K. and Hirao, K. (2000) On the transferability of relativistic pseudopotentials in density-functional calculations AuH, AuCl, and Au2. Chemical Physics Letters, 324, 453-458. 

Wang, F. and Liu, W. (2005) Benchmark four-component relativistic density functional calculations on Cu2, Ag2, and Au2. Chemical Physics, 311, 63-69. 

Thierfelder, C., Schwerdtfeger, P. and Saue, T. (2007) Cu and Au Nuclear Quadrupole Moments from Four-Component Relativistic Density Functional Calculations using Exact Long-Range Exchange. Physical Review A, 76, 034502-1-034502-4. 

Gilb, S., Weis, P., Furche, F., Ahlrichs, R. and Kappes, M.M. (2002) Structures of small gold cluster cations (Au u< 14) Ion mobility measurements versus density functional calculations. Journal of Chemical Physics, 116, 4094—4101. 

Sohnel, T, Hermann, H.L. and Schwerdtfeger, P. (2005) Solid State Density Functional Calculations for the Group 11 Monohalides. The Journal of Physical Chemistry. B, 109, 526—531. 

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