Joniserat

Joniserat is the term used to describe matter that has undergone ionization, meaning it has lost or gained electrons and exists as charged particles called ions. In physics and chemistry, an atom or molecule is ionized when its electron cloud is reduced or expanded by energy input, producing a positively charged ion (cation) if electrons are removed, or a negatively charged ion (anion) if electrons are added. The term is commonly used in Swedish-language texts and is equivalent to “ionized” in English.

Ionization requires energy. The minimum energy needed to remove the outermost electron is called the ionization energy; successive ionizations require progressively larger energies. Ionization can occur through heat, electromagnetic radiation (photoionization), or particle collisions. In mass spectrometry and analytical chemistry, controlled ionization methods such as electron impact or chemical ionization are used to produce ions from neutral molecules.

In many environments, especially hot plasmas, a large fraction of atoms are ionized, giving rise to plasma properties such as electrical conductivity and collective behavior. Ionization states are used to describe chemical species, e.g., Fe2+ or Fe3+ in solution, often denoted by Roman numerals. Ionized species have characteristic spectra and reactivities that differ from their neutral counterparts.

Applications of ionization span multiple fields. In astrophysics, ionized gas traces stellar and interstellar processes. In analytical chemistry and biomedicine, ionization is essential for techniques like mass spectrometry. In electronics, plasma processes rely on ionized gases for etching and deposition. Ionizing radiation can also damage biological tissue, reflecting a safety aspect of ionized particles.