the nearly free electron model (or NFE model and quasi-free electron model) is a quantum mechanical model of physical properties of electrons that can...

In solid-state physics, the free electron model is a quantum mechanical model for the behaviour of charge carriers in a metallic solid. It was developed...

with two complementary models for electrons in solids.: 161  The first one is the nearly free electron model, in which the electrons are assumed to move...

band structure Nearly-free electron model Bloch's theorems Kronig-Penney model Fermi surface Wannier function Hubbard model t-J model Effective mass Anderson's...

Independent electron approximation Lone pair or free electron pair Nearly free electron model Orbital angular momentum of free electrons Unpaired electron This...

potential of the lattice in this free electron model must be weak because otherwise the electrons wouldn't be free. The strength of the scattering mainly...

of electron correlation effects into the methods. Within the framework of Hartree–Fock calculations, some pieces of information (such as two-electron integrals)...

electron model and its further extension, the nearly free electron model. In both models, the electrons are seen as a gas traveling through the structure...

orbital-free density functional theory. Working independently, Thomas and Fermi used this model in 1927 to approximate the distribution of electrons in an...

insulators. The nearly free electron model is a modification of the free electron model which includes a weak periodic perturbation meant to model the interaction...

Perdew–Burke–Ernzerhof exchange model (a direct generalized gradient parameterization of the free-electron gas with no free parameters); however, this is...

which valence bond theory cannot explain. In molecular orbital theory, electrons in a molecule are not assigned to individual chemical bonds between atoms...

the dispersion relation. Models of solids and crystals: Tight-binding model Free electron model Nearly free electron model Kittel, Introduction to Solid...

Kane). According to quantum mechanics (in the single-electron approximation), the quasi-free electrons in any solid are characterized by wavefunctions which...

theory similar to Lewis' only his model assumed complete transfers of electrons between atoms, and was thus a model of ionic bonding. Both Lewis and Kossel...

Electronic band structure Nearly free electron model Periodic boundary conditions Symmetries in quantum mechanics Tight-binding model Wannier function Bloch...

particles. Usual models are the free electron model and the nearly free electron model. In the appropriate systems, the free electron pressure can be calculated;...

inverse of the typical separation) The electron gas dielectric function in the simplest Thomas–Fermi screening model for a wave vector q {\displaystyle q}...

surface. The nearly free electron model adapts the Fermi gas model to consider the crystal structure of metals and semiconductors, where electrons in a crystal...

law). The existence of a non-zero quantum defect was attributed to electron–electron repulsion, which clearly does not exist in the isolated hydrogen atom...

problems. Diffusion Monte Carlo: The most common high-accuracy method for electrons (that is, chemical problems), since it comes quite close to the exact...

(φ1)2, which means that the molecular orbital φ1 is nearly doubly occupied. The Hartree–Fock (HF) model assumes that it is doubly occupied, which leads to...

Fentress, a military airport in Virginia, USA (by FAA LID code) Nearly free electron model Non-formal education New French Extremity Nordisk familjebok ecology...

electromagnetic field so electrons are subject to a regular potential inside the lattice. It is a generalization of the free electron model, which assumes zero...

field (SCF), method. They add electron correlation which is a more accurate way of including the repulsions between electrons than in the Hartree–Fock method...

Thomson, now known as the plum pudding model, was the best available.: 37  Thomson proposed a model with electrons rotating in coplanar rings within an...

and binding energy of a metal. Various models are applicable, the simplest being the nearly free electron model. Modern methods such as density functional...

energy operator, W the electron-electron interaction, and Vext(t) the external potential which along with the number of electrons defines the system. Nominally...

within the Born–Oppenheimer approximation for a quantum chemical multi-electron system. Mathematically, configuration simply describes the linear combination...

are more computationally convenient, and provides a way to calculate all-electron properties from these smooth wavefunctions. This approach is somewhat reminiscent...