Publication

Si 2p core-level shifts in small molecules: A first principles study

Alfredo Pasquarello
1996
Journal Articles

Abstract

Si 2p con-level shifts for a series of molecules are calculated within the local density approximation to density functional theory. Using a pseudopotential approach, the shifts are calculated both in the initial-state approximation and including core-hole relaxation effects. Overall, calculated Si 2p shifts show good agreement with experiment.

Official source

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Alfredo Pasquarello
1996
Journal Articles

Abstract

Official source

Related concepts (15)

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.

Local-density approximation

Local-density approximations (LDA) are a class of approximations to the exchange–correlation (XC) energy functional in density functional theory (DFT) that depend solely upon the value of the electronic density at each point in space (and not, for example, derivatives of the density or the Kohn–Sham orbitals). Many approaches can yield local approximations to the XC energy. However, overwhelmingly successful local approximations are those that have been derived from the homogeneous electron gas (HEG) model.

Electron density

Electron density or electronic density is the measure of the probability of an electron being present at an infinitesimal element of space surrounding any given point. It is a scalar quantity depending upon three spatial variables and is typically denoted as either or . The density is determined, through definition, by the normalised -electron wavefunction which itself depends upon variables ( spatial and spin coordinates). Conversely, the density determines the wave function modulo up to a phase factor, providing the formal foundation of density functional theory.

Related publications (2)

Si 2p core-level shifts in small molecules: A first principles study

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Efficient Krylov Methods for Linear Response in Plane-Wave Electronic Structure Calculations

𝑠⁢𝑝²⁢/𝑠⁢𝑝³ hybridization ratio in amorphous carbon from C 1⁢𝑠 core-level shifts: X-ray photoelectron spectroscopy and first-principles calculation