pseudopotentsiaalidest

Pseudopotential or pseudopotentsiaal is a concept used in physics and chemistry, particularly in computational materials science. It arises from the observation that the behavior of valence electrons in a solid is significantly different from that of core electrons. Core electrons are tightly bound to the atomic nucleus and their wave functions are strongly peaked near the nucleus. In contrast, valence electrons are responsible for chemical bonding and are found in the outer regions of atoms and molecules.

The core idea of a pseudopotential is to replace the strong attractive potential of the nucleus and the tightly bound core electrons with a weaker, effective potential. This effective potential, the pseudopotential, acts only on the valence electrons. The crucial assumption is that the pseudopotential can mimic the scattering properties of the true ionic potential (nucleus plus core electrons) for valence electrons, without explicitly including the core electrons in the calculation.

This simplification has several advantages. Firstly, it reduces the number of electrons that need to be considered in a calculation, making it computationally much more efficient. Secondly, the pseudowave functions of valence electrons are made smoother and nodeless in the core region, which allows for the use of plane wave basis sets in calculations, further enhancing computational speed. Pseudopotentials are typically constructed to reproduce experimental or ab initio results for atomic or ionic properties, such as ionization energies or scattering phase shifts. Different types of pseudopotentials exist, each with varying levels of approximation and suitability for different applications.