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Atomic electron transition. An electron in a Bohr model atom, moving from quantum level n = 3 to n = 2 and releasing a photon. The energy of an electron is determined by its orbit around the atom. The n = 0 orbit, commonly referred to as the ground state, has the lowest energy of all states in the system. In atomic physics and chemistry, an ...
Selection rule. In physics and chemistry, a selection rule, or transition rule, formally constrains the possible transitions of a system from one quantum state to another. Selection rules have been derived for electromagnetic transitions in molecules, in atoms, in atomic nuclei, and so on. The selection rules may differ according to the ...
Molecular electronic transition. In theoretical chemistry, molecular electronic transitions take place when electrons in a molecule are excited from one energy level to a higher energy level. The energy change associated with this transition provides information on the structure of the molecule and determines many of its properties, such as colour.
The Franck–Condon principle is a statement on allowed vibrational transitions between two different electronic states; other quantum mechanical selection rules may lower the probability of a transition or prohibit it altogether. Rotational selection rules have been neglected in the above derivation.
The electron–hole pair is the fundamental unit of generation and recombination in inorganic semiconductors, corresponding to an electron transitioning between the valence band and the conduction band where generation of an electron is a transition from the valence band to the conduction band and recombination leads to a reverse transition.
Hydrogen line. The hydrogen line, 21 centimeter line, or H I line[a] is a spectral line that is created by a change in the energy state of solitary, electrically neutral hydrogen atoms. It is produced by a spin -flip transition, which means the direction of the electron's spin is reversed relative to the spin of the proton.
Spin transition. The spin transition is an example of transition between two electronic states in molecular chemistry. The ability of an electron to transit from a stable to another stable (or metastable) electronic state in a reversible and detectable fashion, makes these molecular systems appealing in the field of molecular electronics.
The Auger effect (/ oʊˈʒeɪ /; French pronunciation: [ˈ/o.ʒe/]) or Auger−Meitner effect is a physical phenomenon in which the filling of an inner-shell vacancy of an atom is accompanied by the emission of an electron from the same atom. [1] When a core electron is removed, leaving a vacancy, an electron from a higher energy level may ...