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Charge carrier density, also known as carrier concentration, denotes the number of charge carriers per volume. In SI units, it is measured in m −3. As with any density, in principle it can depend on position. However, usually carrier concentration is given as a single number, and represents the average carrier density over the whole material.
Nuclear charge is defined as the number of protons in the nucleus of an element.Thus, from left-to-right of a period and top-to-bottom of a group, as the number of protons in the nucleus increases, the nuclear charge will also increase. [8]
In electromagnetism, charge density is the amount of electric charge per unit length, surface area, or volume. Volume charge density (symbolized by the Greek letter ρ) is the quantity of charge per unit volume, measured in the SI system in coulombs per cubic meter (C⋅m −3), at any point in a volume.
Nuclear density is the density of the nucleus of an atom. For heavy nuclei, it is close to the nuclear saturation density n 0 = 0.15 ± 0.01 {\displaystyle n_{0}=0.15\pm 0.01} nucleons / fm 3 , which minimizes the energy density of an infinite nuclear matter . [ 1 ]
The stable nucleus has approximately a constant density and therefore the nuclear radius R can be approximated by the following formula, R = r 0 A 1 / 3 {\displaystyle R=r_{0}A^{1/3}\,} where A = Atomic mass number (the number of protons Z , plus the number of neutrons N ) and r 0 = 1.25 fm = 1.25 × 10 −15 m.
An important factor in the internal structure of the nucleus is the nucleon-nucleon potential, which ultimately governs the distance between individual nucleons, [3] while a dip in the charge density of some light nuclide structures a lesser density of nucleonic matter. [4]
The electron density of the ground state of a molecular system contains cusps at the location of the nuclei, and by identifying these from the total electron density of the system, the positions are thus established. From Kato's theorem, one also obtains the nuclear charge of the nuclei, and thus the external potential is fully defined.
The Independent Atom Model (abbreviated to IAM), upon which the Multipole Model is based, is a method of charge density modelling. It relies on an assumption that electron distribution around the atom is isotropic, and that therefore charge density is dependent only on the distance from a nucleus.