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Hund's rules. In atomic physics and quantum chemistry, Hund's rules refers to a set of rules that German physicist Friedrich Hund formulated around 1925, which are used to determine the term symbol that corresponds to the ground state of a multi-electron atom. The first rule is especially important in chemistry, where it is often referred to ...
Hund's rule of maximum multiplicity. Hund's rule of maximum multiplicity is a rule based on observation of atomic spectra, which is used to predict the ground state of an atom or molecule with one or more open electronic shells. The rule states that for a given electron configuration, the lowest energy term is the one with the greatest value of ...
Hund's rule asserts that if multiple orbitals of the same energy are available, electrons will occupy different orbitals singly and with the same spin before any are occupied doubly. If double occupation does occur, the Pauli exclusion principle requires that electrons that occupy the same orbital must have different spins (+ 1 ⁄ 2 and − 1 ...
Friedrich Hermann Hund (4 February 1896 – 31 March 1997) was a German physicist from Karlsruhe known for his work on atoms and molecules. [ 1 ] He is known for the Hund's rules to predict the electron configuration of chemical elements. His work on Hund's cases and molecular orbital theory allowed to understand the structure of molecules.
Contents. Electron configuration. In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. [ 1 ] For example, the electron configuration of the neon atom is 1s2 2s2 2p6, meaning that the 1s, 2s, and 2p subshells are ...
The occupation of the electron states in such an atom can be predicted by the Aufbau principle and Hund's empirical rules for the quantum numbers. The Aufbau principle fills orbitals based on their principal and azimuthal quantum numbers (lowest n + l {\displaystyle n+l} first, with lowest n {\displaystyle n} breaking ties; Hund's rule favors ...
An example of Hund's case (c) is the lowest 3 Π u state of diiodine (I 2), which approximates more closely to case (c) than to case (a). [ 6 ] The selection rules for S {\displaystyle S} , Ω {\displaystyle \Omega } and parity are valid as for cases (a) and (b), but there are no rules for Λ {\displaystyle \Lambda } and Σ {\displaystyle ...
e. A quantum mechanical system or particle that is bound —that is, confined spatially—can only take on certain discrete values of energy, called energy levels. This contrasts with classical particles, which can have any amount of energy. The term is commonly used for the energy levels of the electrons in atoms, ions, or molecules, which are ...