Publication

Atom centered potentials for the description and the design of chemical compounds within density functional theory

Anatole von Lilienfeld
2005
Theses

Abstract

Within the Born-Oppenheimer picture of the electronic Schrödinger equation the external potential due to the nuclei influences the resulting expectation values during the self consistent field procedure. In this thesis, the optimization and the benefit of atom centered potentials for an improved description and design of molecules is studied using density functional theory (DFT). It is shown that atom centered potentials can be used to increase the accuracy of the description of molecular properties as well as to generally explore chemical space rationally for structures which exhibit desired properties. The wide range of possible applications is illustrated by addressing several issues. First, an automated procedure is proposed for the design of optimal link pseudopotentials for quantum mechanics/molecular mechanics calculations. Secondly, it is shown how to tune variationally atom centered potentials within density functional perturbation theory in order to minimize the deviation in electron density from an arbitrary reference density. Here, a reference density has been chosen which results from the use of a different exchange-correlation potential. Thirdly, London dispersion interactions are mimicked with dispersion corrected atom centered potentials. Fourthly, the transferability of these dispersion corrected atom centered potentials is assessed. Fifthly, an expression for the molecular nuclear chemical potential is derived within the context of conceptual DFT. It offers the possibility to develop a general formulation for rational compound design via gradient based minimization of a property-penalty functional in chemical space.

Official source

https://infoscience.epfl.ch/entities/publication/9981676a-73ca-4183-b56f-97cb722e191f

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Anatole von Lilienfeld
2005
Theses

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/9981676a-73ca-4183-b56f-97cb722e191f

About this result

Related concepts (32)

Density functional theory

Density-functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases. Using this theory, the properties of a many-electron system can be determined by using functionals, i.e. functions of another function. In the case of DFT, these are functionals of the spatially dependent electron density.

Chemical bond

A chemical bond is a lasting attraction between atoms or ions that enables the formation of molecules, crystals, and other structures. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds, or through the sharing of electrons as in covalent bonds. The strength of chemical bonds varies considerably; there are "strong bonds" or "primary bonds" such as covalent, ionic and metallic bonds, and "weak bonds" or "secondary bonds" such as dipole–dipole interactions, the London dispersion force, and hydrogen bonding.

Quantum chemistry

Quantum chemistry, also called molecular quantum mechanics, is a branch of physical chemistry focused on the application of quantum mechanics to chemical systems, particularly towards the quantum-mechanical calculation of electronic contributions to physical and chemical properties of molecules, materials, and solutions at the atomic level. These calculations include systematically applied approximations intended to make calculations computationally feasible while still capturing as much information about important contributions to the computed wave functions as well as to observable properties such as structures, spectra, and thermodynamic properties.

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