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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 ρ ( r ) {\displaystyle \rho ({\textbf {r}})} or n ( r ) {\displaystyle n ...
The IPP or Ionospheric Pierce Point is the altitude in the ionosphere where electron density is greatest. [1] These points can change based on factors like time of day, solar activity, and geographical location, which all influence ionospheric conditions. [2]
The Fukui function quantifies this change in electron density at a given position when the number of electrons have been changed. This function is as follows: = where () is the electron density. The Fukui function itself has two finite versions of this change which can be defined by the following two functions.
Also, in 1927, Albrecht Unsöld proved that if one sums the electron density of all orbitals of a particular azimuthal quantum number ℓ of the same shell n (e.g., all three 2p orbitals, or all five 3d orbitals) where each orbital is occupied by an electron or each is occupied by an electron pair, then all angular dependence disappears; that ...
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.
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.
In structural biology, resolution can be broken down into 4 groups: (1) sub-atomic, when information about the electron density is obtained and quantum effects can be studied, (2) atomic, individual atoms are visible and an accurate three-dimensional model can be constructed, (3) helical, secondary structure, such as alpha helices and beta sheets; RNA helices (in ribosomes), (4) domain, no ...
In a simulation, the potential energy of an atom, , is given by [3] = (()) + (), where is the distance between atoms and , is a pair-wise potential function, is the contribution to the electron charge density from atom of type at the location of atom , and is an embedding function that represents the energy required to place atom of type into the electron cloud.