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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 simply as Hund's ...
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 ...
Later, K. Deilamian et al. [12] used an atomic beam spectrometer to search for the paronic state 1s2s 1 S 0 calculated by Drake. The search was unsuccessful and showed that the statistical weight of this paronic state has an upper limit of 5 × 10 −6. (The exclusion principle implies a weight of zero.)
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 spin multiplicity . [ 1 ]
Neutral atoms of the chemical elements have the same term symbol for each column in the s-block and p-block elements, but differ in d-block and f-block elements where the ground-state electron configuration changes within a column, where exceptions to Hund's rules occur. Ground state term symbols for the chemical elements are given below.
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.
Hund's rules are three rules in atomic physics used to determine the term symbol that corresponds to the ground state of a multi-electron atom. Named after Friedrich Hund. Hutber's law: "Improvement means deterioration."
In chemistry and physics, the exchange interaction is a quantum mechanical constraint on the states of indistinguishable particles.While sometimes called an exchange force, or, in the case of fermions, Pauli repulsion, its consequences cannot always be predicted based on classical ideas of force. [1]