Development of the Orbital-Free Density Functional Approach: The Problem of Angles between Covalent Bonds

Abstract

The Paulie's principle is used for development of the orbital-free (OF) version of the density functional theory. On the example of the three-atomic clusters, Al 3 , Si 3 , and C 3 , it is shown that the OF approach may lead to equilibrium configurations of atomic systems with both the metallic and covalent bonding. The equilibrium interatomic distances, interbonding angles and binding energies are found in good accordance with the known data. Results will be useful for developing of theoretical study of huge molecules and nanoparticles.