New Orbital-Free Approach for Density Functional Modeling of Large Molecules and Nanoparticles

V Zavodinsky,O Gorkusha

doi:10.4236/mnsms.2015.52004

V Zavodinsky, O Gorkusha

Open Access

https://doi.org/10.4236/mnsms.2015.52004

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Abstract

Development of the orbital-free (OF) approach of the density functional theory (DFT) may result in a power instrument for modeling of complicated nanosystems with a huge number of atoms. A key problem on this way is calculation of the kinetic energy. We demonstrate how it is possible to create the OF kinetic energy functionals using results of Kohn-Sham calculations for single atoms. Calculations provided with these functionals for dimers of sp-elements of the C, Si, and Ge periodic table rows show a good accordance with the Kohn-Sham DFT results.

Highlights

The modern materials science and macromolecular chemistry combining nano, micro, and macro scales represent special inquiries to modeling of atomic interactions
Intensive attempts to develop an orbital-free (OF) approach for modeling of polyatomic systems based on the density functional theory (DFT) [1] were made by a number of groups in last two decades [2]-[10]
In our recent papers [17] [18], we have showed how it is possible, using single-atoms calculations by the Kohn-Sham DFT method (KS-DFT) [19], to find numerically the kinetic energy functionals for atoms, and to use them for orbital-free modeling of atomic interactions

Summary

Introduction

The modern materials science and macromolecular chemistry combining nano, micro, and macro scales represent special inquiries to modeling of atomic interactions. When the system contains millions or billions of electrons, the task to find its quantum-mechanical state using wave functions (orbitals) becomes almost insoluble. Intensive attempts to develop an orbital-free (OF) approach for modeling of polyatomic systems based on the density functional theory (DFT) [1] were made by a number of groups in last two decades [2]-[10]. Most of them were developed within a pseudopotential approach, recently even an all-electron version of the OF method appeared [11]. The reason of this unluckiness is that all OF works stand on idea of using some universal functionals for kinetic energy—in approaches of Tomas-Fermi [12] [13], Weizsacker [14], and their modifications and combinations

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Conclusion