Physical world and mathematics

Ion mobility separation

Ion mobility separation, also known as ion mobility spectrometry (IMS), is a mass spectrometry technique that separates gas-phase ions by size and shape, and is used in laboratories and portable detectors for explosives.

Ion mobility spectrometry

Ion mobility spectrometry, also known as differential mobility analysis, is an analytical technique that separates gas-phase ions by drift speed in a buffer gas, yielding collision cross sections used to distinguish isomers.

Ion pairing

Ion pairing is the association of an oppositely charged cation and anion in solution by Coulomb attraction without a covalent bond, a concept introduced by Niels Bjerrum in 1926.

Ion pump (vacuum)

An ion pump, also called a sputter ion pump, is a vacuum pump with no moving parts that maintains ultra-high vacuum by trapping ionized gas in titanium films.

Ion scattering spectroscopy

Ion scattering spectroscopy (ISS) is a surface analysis technique that determines the elemental composition of a material's outermost atomic layer by bombarding it with ions and measuring those scattered back.

Ion shuttling

Ion shuttling is the transport of trapped-ion qubits between zones of an ion-trap chip using controlled electric fields, moving quantum information for gates, measurements, or storage.

Ion temperature gradient mode

The ion temperature gradient (ITG) mode is a drift-wave micro-instability of magnetically confined fusion plasmas, the principal driver of anomalous ion heat transport in tokamaks.

Ion trap

An ion trap is a device that holds charged particles in place using electric and magnetic fields, most often as a Penning trap or a Paul trap.

Ion trap mass spectrometry

Ion trap mass spectrometry (IT-MS) is a mass spectrometry technique that stores ions in a radiofrequency quadrupole field, performing tandem MS in time up to MS10.

Ion trapping

Ion trapping is the accumulation of residual-gas ions in the negative potential of an electron beam, causing tune shifts, emittance growth, and beam instabilities in storage rings.

Ion-exchange resin

An ion-exchange resin, also called an ion-exchange polymer, is an insoluble cross-linked polymer bead that reversibly exchanges ions with solution, used in water softening and demineralization.

Ion-gated superconductivity in 2D materials

Ion-gated superconductivity in 2D materials is the voltage-tuned induction of superconductivity in atomically thin crystals using an electrolyte gate, first demonstrated in MoS₂ by University of Tokyo researchers in 2012.

Ion-pair chromatography

Ion-pair chromatography is a liquid chromatography technique that adds a charged reagent to the mobile phase to retain ionic and strongly polar compounds on a reversed-phase column.

Ion-photon entanglement

Ion-photon entanglement is entanglement between a trapped atomic ion qubit and a single photon it emits, which carries the ion's quantum information through fiber as a flying qubit.

Ion-selective electrode

An ion-selective electrode (ISE) is an electrochemical sensor with a selective membrane whose potential, read against a reference electrode and calibrated, gives the activity of a chosen ion in solution.

Ionic bonding

Ionic bonding, also known as electrovalent bonding, is the electrostatic attraction holding oppositely charged cations and anions together in a crystal lattice, as in sodium chloride.

Ionic conductivity

Ionic conductivity measures how much ionic current a material carries per unit electric field, in siemens per meter, and is the central transport property of battery and solid electrolytes.

Ionic liquid

An ionic liquid is a salt that melts below 100 °C, usually a bulky organic cation paired with an organic or inorganic anion, giving low volatility.

Ionic liquid assisted synthesis

Ionic liquid assisted synthesis prepares zeolites, metal–organic frameworks, and nanoparticles using an ionic liquid, molten below 100 °C, as solvent, template, or stabilizer, first reported in 2004.

Ionic liquid-enhanced CO2 electroreduction

Ionic liquid-enhanced CO2 electroreduction is the electrochemical reduction of carbon dioxide in electrolytes containing ionic liquids, which lower overpotentials to about 50–150 mV and improve selectivity for fuels and chemicals.

Ionic liquids for carbon capture

Ionic liquids for carbon capture are room-temperature molten salts used as solvents, membranes, or sorbents to absorb CO2, studied as alternatives to energy-intensive amine solvents like MEA.

Ionic mobility

Ionic mobility is the drift velocity an ion attains in solution per unit electric field, independent of field strength and interchangeable with molar conductivity in describing electrolytes.

Ionic potential

Ionic potential is a chemical parameter introduced by G. H. Cartledge in 1928, defined as an ion's charge divided by its ionic radius, measuring its interaction strength.

Ionic radius

Ionic radius (ionic radii) is the effective size of an ion in a crystal, defined so cation and anion radii sum to the measured distance between nuclei.

Ionic strength

Ionic strength (symbol I) is a measure of the total electrostatic environment of a solution, defined as half the sum of each ion's concentration times its charge squared.

Ionic thermoelectric

An ionic thermoelectric material converts a temperature difference into an electrical voltage using ions instead of electrons, with giant thermopowers of tens of mV/K suited to harvesting low-grade body and waste heat.

Ionic thermoelectric effect

The ionic thermoelectric effect is the generation of thermovoltage in ion-conducting materials like hydrogels when a temperature gradient is applied, with ions rather than electrons as charge carriers.

Ionization

Ionization is the process by which neutral atoms or molecules are converted into electrically charged ions, commonly by gaining or losing electrons, requiring the ionization energy.

Ionization chamber

An ionization chamber, or ion chamber, is a gas-filled radiation detector that collects ion pairs directly at two electrodes, serving as a standard dosimetry instrument.