Spectroscopic and elastic properties in metallic systems from first-principles methods

• In this thesis, ab initio calculations on metallic systems are presented. The overall aim is to probe properties that are often considered to be difficult to obtain within the framework of density-functional theory. The aim has also been to chose problems and systems that are of a wider interest and not only a testbed for calculations.One of the properties investigated is the binding-energy shifts for core electrons in binary alloys of face-centered cubic structure using different theoretical methods. These methods are compared with each other and with experimental results. One of the methods, the so-called Slater-Jank transition state method has been investigated in more detail. This method relies on the assumption that the single-particle eigenvalues within density-functional theory are linear functions of their respective occupation number. This assumption is investigated , and it is found that while the eigenvalues to a first approximation show linear behaviour, the Slater-Jank transition state method can be improved by a first-order correction to the non-linearities.Another area of investigation have been FeNi systems at high pressure. Calculations of elastic constants in this alloy at pressures corresponding to the Earth's core have been done for the hexagonal close packed and face centered cubic structures. These calculations show that, contrary to many other systems, the hexagonal close packed structure in FeNi is more isotropic than the face centered cubic structure.

Nyckelord

NATURAL SCIENCES

NATURVETENSKAP

Publikations- och innehållstyp

vet (ämneskategori)

lic (ämneskategori)