OF-DFT/MCHF · Orbital Free Density Functional Theory: insights from quantum chemistry and atomic physics

This proposal aims to put me at the forefront of research in two related domains: quantum chemistry and atomic physics. These domains have the same origin in finding solutions to the Schrödinger equation. Although the methods in both domains stem from the same ab initio approach, they departed from their common ground and developed methods specific to their problems. A few decades ago a revolutionary method came to quantum chemistry: Density Functional Theory (DFT). In this theory the electronic density function replaces the traditional, more complicated wave function to describe the electronic structure of molecules. The implications for computational chemistry have been astounding. The successful development of density functionals to evaluate a system's energy, has made DFT a powerful tool, with applications from bio-chemistry to chemical reactivity. It has become the most popular quantum chemical tool. Today's calculations typically use the Kohn-Sham method which implies the introduction of orbitals, departing from the original spirit of the density-only theory. Motivated by their computational attractiveness (linear scaling, no orthonormalization,no Brillouin zone sampling) researchers have taken up the challenge to design orbital free functionals. This project aims towards the construction and evaluation of such orbital free functionals. Since DFT approaches, remarkably, never found their way to atomic physics, where their potential is evident and since ab initio methods from atomic physics still provide the highest quality density functions (corresponding to an eigenstate), the objectives in this project propose a synergy of concepts, methods and fundamental aspects in both fields. For the successful execution of this interdisciplinary proposal, milestones have been identified which, with the appropriate training, based on the experience and knowledge on functional development of Professor Tozer, is expected to lead to high quality publications.