Density functional approaches

A1.3.3 DENSITY FUNCTIONAL APPROACHES TO QUANTUM DESCRIPTIONS OF CONDENSED PHASES... 

There are a variety of other approaches to understanding the electronic structure of crystals. Most of them rely on a density functional approach, with or without the pseudopotential, and use different bases. For example, instead of a plane wave basis, one might write a basis composed of atomic-like orbitals ... 

Many of the various density functional approaches that are under active development can be found in ... 

Kruger S, Birkenheuer U and Rdsch N 1994 Density functional approach to moderately large cluster embedding for infinite metal substrates J. Eleotron Speotroso. Relat Phenom. 69 31... 

Wesolowski T A and Warshel A 1993 Frozen density functional approach to ah initio calculations of solvated molecules J. Phys. Chem. 97 8050... 

We have extended the linear combination of Gaussian-type orbitals local-density functional approach to calculate the total energies and electronic structures of helical chain polymers[35]. This method was originally developed for molecular systems[36-40], and extended to two-dimensionally periodic sys-tems[41,42] and chain polymers[34j. The one-electron wavefunctions here are constructed from a linear combination of Bloch functions c>>, which are in turn constructed from a linear combination of nuclear-centered Gaussian-type orbitals Xylr) (in ihis case, products of Gaussians and the real solid spherical harmonics). The one-electron density matrix is given by... 

D. Henderson, S. Sokolowski, D. Wasan. Structure of a hard-sphere fluid near a rough surface a density-functional approach. Phys Rev E 57 5539-5543, 1998. 

Local Density from a Density Functional Approach... 

The density functional approach of Refs. 91, 92 introduces a correction to the wall-particle direct correlation function resulting from the HNCl approximation (see Eqs. (32)-(34)). A correction to Eq. (34) reads (we drop the species label because the model is one-component)... 

FIG. 6 A comparison of the Monte Carlo (points), HHNCl, HNCl, and PYl density profiles. The results are for bulk density 0.403 (lower group of curves) and 0.741 (upper group of curves). The curves at z — 0, are, from the bottom, from HHNCl and HNCl approximations. (Reprinted from A. Trokhymchuk, D. Henderson, S. Sokolowski. Local density of overlapping spheres near a hard wall A density functional approach. Physics Letters A 209, 317-320. 1995, with permission from Elsevier Science.)... 

The problem of adsorption of associating fluids on crystalline surfaces has also been studied by Borowko et al. by using the density functional approach [43]. 

IV. DENSITY FUNCTIONAL APPROACHES IN THE THEORY OF INHOMOGENEOUS ASSOCIATING FLUIDS... 

The density functional approach has also been used to study capillary condensation in slit-like pores [148,149]. As in the previous section, a simple model of the Lennard-Jones associating fluid with a single associative site is considered. All the parameters of the interparticle potentials are chosen the same as in the previous section. Our attention has been focused on the influence of association on capillary condensation and the evaluation of the phase diagram [42]. 

Barone, V., Orlandini, L., Adamo, C., 1994b, Proton Transfer in Model Hydrogen-Bonded Systems by a Density Functional Approach , Chem. Phys. Lett., 231, 295. 

Filatov, M., Shaik, S., 1998a, Spin-Restricted Density Functional Approach to the Open-Shell Problem , Chem. Phys. Lett., 288, 689. 

Gonzales, L., Mo, O., Yanez, M., Elguerdo, J., 1996, Cooperative Effects in Water Trimers. The Performance of Density Functional Approaches , J. Mol. Struct. (Theochem), 371, 1. 

St. Amant, A., 1996, Practical Density Functional Approaches in Chemistry and Biochemistry in Quantum Mechanical Simulation Methods for Studying Biological Systems, Bicout, D., Field, M. (eds.), Springer, Heidelberg. 

With the addition of a pseudopotential interaction between electrons and metal ions, the density-functional approach has been used82 to calculate the effect of the solvent of the electrolyte phase on the potential difference across the surface of a liquid metal. The solvent is modeled as a repulsive barrier or as a region of dielectric constant greater than unity or both. Assuming no specific adsorption, the metal is supposed to be in contact with a monolayer of water, modeled as a region of 3-A thickness (diameter of a water molecule) in which the dielectric constant is 6 (high-frequency value, appropriate for nonorientable dipoles). Beyond this monolayer, the dielectric constant is assumed to take on the bulk liquid value of 78, although the calculations showed that the dielectric constant outside of the monolayer had only a small effect on the electronic profile. 

Murray, J. S., J. M. Seminario, M. C. Concha, and P. Politzer. 1992. An Analysis of Molecular Electrostatic Potentials Obtained by a Local Density Functional Approach. Int. J. Quant. Chem. 44,113. 

In a contrary to the DFT studies of isolated molecules, where there is a strong link between applications to biological systems and general developments in the theory of density functionals, approaches used for modeling properties of chemical molecules embedded in the biological microscopic environment combine developments in many fields. These fields include DFT, statistical physics, dielectric theory, and the theory of liquids. 

Barone, V., C. Adamo, and F. Lelj. 1995. Conformational behavior of gaseous glycine by a density functional approach. J. Chem. Phys. 102, 364. 

Tornaghi, E., W. Andreoni, P. Carloni, J. Hutter, and M. Parrinello. 1995. Carboplatin versus cisplatin density functional approach to their molecular properties. Chem. Phys. Lett. 246, 469. 

Wesolowski, T. A. and A. Warshel. 1993. Frozen Density Functional Approach for ab initio Calculations of Solvated Molecules. 

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