Electron density is the measure of the probability of an electron being present at a specific location. Probability is the likelihood or chance that something is the case or will happen The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J

In molecules, regions of electron density are usually found around the atom, and its bonds. In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny In de-localized or conjugated systems, such as phenol, benzene and compounds such as hemoglobin and chlorophyll, the electron density covers an entire region, i. A chemically conjugated system is a system of atoms Covalently bonded with alternating single and multiple (e Phenol, is a toxic colourless Crystalline Solid with a sweet tarry odor commonly referred to as a "hospital smell" Benzene, or benzol, is an organic Chemical compound and a known Carcinogen with the molecular formula C 6 H 6 Hemoglobin ( also spelled haemoglobin and abbreviated Hb or Hgb) is the Iron -containing Oxygen -transport Metalloprotein Chlorophyll is a green Pigment found in most Plants Algae and Cyanobacteria. e. , in benzene they are found above and below the planar ring. This is sometimes shown diagrammatically as a series of alternating single and double bonds. In the case of phenol and benzene, a circle inside a hexagon shows the de-localized nature of the compound. Regular hexagon The internal Angles of a regular hexagon (one where all sides and all angles are equal are all 120 ° and the hexagon has 720 degrees This is shown below:

In compounds with multiple ring systems which are interconnected, this is no longer accurate, so alternating single and double bonds are used. In compounds such as chlorophyll and phenol, some diagrams show a dotted or dashed line to represent the de-localization of areas where the electron density is higher next to the single bonds ^[1]. Conjugated systems can sometimes represent regions where electromagnetic radiation is absorbed at different wavelengths resulting in compounds appearing coloured. Electromagnetic radiation takes the form of self-propagating Waves in a Vacuum or in Matter. In polymers, these areas are known as chromophores. A polymer is a large Molecule ( Macromolecule) composed of repeating Structural units typically connected by Covalent Chemical bonds

Electron densities are sometimes probed with X-ray diffraction scans, where X-rays of a suitable wavelength are targeted towards a sample and measurements are made over time to represent, probabilistically, where electrons can be found. X-ray scattering techniques are a family of non-destructive analytical techniques which reveal information about the crystallographic structure chemical composition Quantum electrodynamics and some branches of quantum theory also study and analyze electron superposition and other phenomena. Quantum electrodynamics ( QED) is a relativistic Quantum field theory of Electrodynamics. In quantum field theory (QFT the forces between particles are mediated by other particles Quantum tunneling and quantum entanglement are interesting areas involving electrons (or photons). In Quantum mechanics, quantum tunnelling is a nanoscopic phenomenon in which a particle violates the principles of Classical mechanics by penetrating a Quantum entanglement is a quantum mechanical Phenomenon in which the Quantum states of two or more objects are linked together so that one object The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena High speed electrons are often used in transmission electron micrography (or microscopy, TEM) and deep inelastic scattering, as well as many other high-speed particle experiments involving electrons. In Particle physics and Chemistry, inelastic scattering is a fundamental Scattering process in which the kinetic energy of an incident particle is not conserved

Mulliken population analysis is based on electron densities in molecules and is a way of dividing the density between atoms to give an estimate of atomic charges. Mulliken charges arise from the Mulliken population analysis and provide a means of estimating partial atomic charges from calculations carried out by the methods

Spin density

Spin density is electron density applied to free radicals. In Chemistry, radicals (often referred to as free radicals) are atoms molecules or ions with Unpaired electrons on an otherwise Open shell It is defined as the total electron density of electrons of one spin minus the total electron density of the electrons of the other spin. One of the ways to measure it experimentally is by electron spin resonance ^[2]. Electron paramagnetic resonance (EPR or electron spin resonance (ESR Spectroscopy is a technique for studying Chemical species that have one or more unpaired

See also

• Electron configuration
• Electron cloud
• Resolution (electron density)

References

1. ^ e. In Atomic physics and Quantum chemistry, electron configuration is the arrangement of Electrons in an Atom, Molecule, or other Electron cloud is a term used if not originally coined by the Nobel Prize laureate and acclaimed educator Richard Feynman in The Feynman Lectures on Physics Resolution in terms of electron density is a measure of the resolvability in the electron density map of a molecule g. , the white line in the diagram on Chlorophylls and Carotenoids
2. ^ IUPAC Gold BookLink