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  2. Cavity perturbation theory - Wikipedia

    en.wikipedia.org/wiki/Cavity_perturbation_theory

    It is convenient to denote cavity frequencies with a complex number ~ = /, where = (~) is the angular resonant frequency and = (~) is the inverse of the mode lifetime. Cavity perturbation theory has been initially proposed by Bethe-Schwinger in optics [1], and Waldron in the radio frequency domain. [2]

  3. Resonance - Wikipedia

    en.wikipedia.org/wiki/Resonance

    Pushing a person in a swing is a common example of resonance. The loaded swing, a pendulum, has a natural frequency of oscillation, its resonant frequency, and resists being pushed at a faster or slower rate. A familiar example is a playground swing, which acts as a pendulum. Pushing a person in a swing in time with the natural interval of the ...

  4. Resonance (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Resonance_(chemistry)

    Contributing structures of the carbonate ion. In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or forms, [1] also variously known as resonance structures or canonical structures) into a resonance hybrid (or hybrid structure) in valence bond theory.

  5. Mesomeric effect - Wikipedia

    en.wikipedia.org/wiki/Mesomeric_effect

    In chemistry, the mesomeric effect (or resonance effect) is a property of substituents or functional groups in a chemical compound. It is defined as the polarity produced in the molecule by the interaction of two pi bonds or between a pi bond and lone pair of electrons present on an adjacent atom. [ 1 ]

  6. Helmholtz resonance - Wikipedia

    en.wikipedia.org/wiki/Helmholtz_resonance

    Helmholtz resonance, also known as wind throb, refers to the phenomenon of air resonance in a cavity, an effect named after the German physicist Hermann von Helmholtz. [1] This type of resonance occurs when air is forced in and out of a cavity (the resonance chamber ), causing the air inside to vibrate at a specific natural frequency .

  7. Jahn–Teller effect - Wikipedia

    en.wikipedia.org/wiki/Jahn–Teller_effect

    The Jahn–Teller effect (JT effect or JTE) is an important mechanism of spontaneous symmetry breaking in molecular and solid-state systems which has far-reaching consequences in different fields, and is responsible for a variety of phenomena in spectroscopy, stereochemistry, crystal chemistry, molecular and solid-state physics, and materials science.

  8. Molecular orbital theory - Wikipedia

    en.wikipedia.org/wiki/Molecular_orbital_theory

    When one electron is removed from an sp 3 orbital, resonance is invoked between four valence bond structures, each of which has a single one-electron bond and three two-electron bonds. Triply degenerate T 2 and A 1 ionized states (CH 4 + ) are produced from different linear combinations of these four structures.

  9. VSEPR theory - Wikipedia

    en.wikipedia.org/wiki/VSEPR_theory

    The steric number of a central atom in a molecule is the number of atoms bonded to that central atom, called its coordination number, plus the number of lone pairs of valence electrons on the central atom. [11] In the molecule SF 4, for example, the central sulfur atom has four ligands; the coordination number of sulfur is four. In addition to ...