When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Photoionization detector - Wikipedia

    en.wikipedia.org/wiki/Photoionization_detector

    In a photoionization detector, high-energy photons, typically in the vacuum ultraviolet (VUV) range, break molecules into positively charged ions. [2] As compounds enter the detector they are bombarded by high-energy UV photons and are ionized when they absorb the UV light, resulting in ejection of electrons and the formation of positively charged ions.

  3. Proportional–integral–derivative controller - Wikipedia

    en.wikipedia.org/wiki/Proportional–integral...

    PID controllers work best when the loop to be controlled is linear and symmetric. Thus, their performance in non-linear and asymmetric systems is degraded. A non-linear valve, for instance, in a flow control application, will result in variable loop sensitivity, requiring dampened action to prevent instability.

  4. Appearance energy - Wikipedia

    en.wikipedia.org/wiki/Appearance_energy

    Appearance energy (also known as appearance potential) is the minimum energy that must be supplied to a gas phase atom or molecule in order to produce an ion. In mass spectrometry, it is accounted as the voltage to correspond for electron ionization. [1] This is the minimum electron energy that produces an ion. [2]

  5. Photoionization - Wikipedia

    en.wikipedia.org/wiki/Photoionization

    When either the laser intensity is further increased or a longer wavelength is applied as compared with the regime in which multi-photon ionization takes place, a quasi-stationary approach can be used and results in the distortion of the atomic potential in such a way that only a relatively low and narrow barrier between a bound state and the continuum states remains.

  6. Ion - Wikipedia

    en.wikipedia.org/wiki/Ion

    The energy required to detach an electron in its lowest energy state from an atom or molecule of a gas with less net electric charge is called the ionization potential, or ionization energy. The nth ionization energy of an atom is the energy required to detach its nth electron after the first n − 1 electrons have already been detached.

  7. Ionic potential - Wikipedia

    en.wikipedia.org/wiki/Ionic_potential

    Ionic potential is the ratio of the electrical charge (z) to the radius (r) of an ion. [1]= = As such, this ratio is a measure of the charge density at the surface of the ion; usually the denser the charge, the stronger the bond formed by the ion with ions of opposite charge.

  8. HSAB theory - Wikipedia

    en.wikipedia.org/wiki/HSAB_theory

    where I is the ionization potential and A the electron affinity. This expression implies that the chemical hardness is proportional to the band gap of a chemical system, when a gap exists. The first derivative of the energy with respect to the number of electrons is equal to the chemical potential, μ, of the system,

  9. Ionization potential - Wikipedia

    en.wikipedia.org/?title=Ionization_potential&...

    Pages for logged out editors learn more. Contributions; Talk; Ionization potential