A Performance Analysis of ABINIT on a Cluster System

in which the Hamilton operator Ĥtot describes all interactions within the system. The solution Φ, the wavefunction of the system, describes the state of all N electrons and M atomic nuclei, and Etot is the total energy of this state. Usually, the problem is split by separating the electronic from the ionic part by making use of the Born-Oppenheimer approximation [1]. Next we consider the electrons as independent particles, represented by one-electron wavefunctions φi. Density functional theory (DFT), based on the work of Hohenberg and Kohn [2] and Kohn and Sham [3], then enables us to represent the total electronic energy of the system by a functional of the electron density n(r):