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Ionization or ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an ion .
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. Each successive ionization energy is markedly greater than the last. Particularly great increases occur after any given block of atomic orbitals is exhausted of electrons. For this reason, ions ...
Chemical ionization in an atmospheric pressure electric discharge is called atmospheric pressure chemical ionization (APCI), which usually uses water as the reagent gas. An APCI source is composed of a liquid chromatography outlet, nebulizing the eluent, a heated vaporizer tube, a corona discharge needle and a pinhole entrance to 10 −3 torr ...
The electron is then ejected from this excited state and not from the ground state, as happens for the one-photon ionization. This ionization mode started to be used already from the 1980sin order to characterize chemically the final DNA lesions (single and double strand breaks, 8-oxo-7,8-dihydroguanine,..), stemming from this process. [39]
Electron capture ionization (ECI) is the ionization of a gas phase atom or molecule by attachment of an electron to create an ion of the form A −•.The reaction is + where the M over the arrow denotes that to conserve energy and momentum a third body is required (the molecularity of the reaction is three).
A certain amount of energy, which may be large enough, is required to remove an electron from an atom or a molecule in its ground state. [12] [13] In chemi-ionization processes, the energy consumed by the ionization must be stored in atoms or molecules in a form of potencial energy or can be obtained from an accompanying exothermic chemical change (for example, from a formation of a new ...
Electron ionization. Electron ionization (EI, formerly known as electron impact ionization [1] and electron bombardment ionization [2]) is an ionization method in which energetic electrons interact with solid or gas phase atoms or molecules to produce ions. [3] EI was one of the first ionization techniques developed for mass spectrometry. [4]
Penning ionization is a form of chemi-ionization, an ionization process involving reactions between neutral atoms or molecules. [1] [2] The Penning effect is put to practical use in applications such as gas-discharge neon lamps and fluorescent lamps, where the lamp is filled with a Penning mixture to improve the electrical characteristics of the lamps.