impact ionization

Impact ionization is a process where an energetic particle, such as an electron, collides with an atom or molecule, transferring enough energy to eject another electron. This results in the creation of two free electrons and a positively charged ion. This phenomenon is fundamental in understanding how matter interacts with high-energy radiation and charged particles.12

In mass spectrometry, electron bombardment is a common method for ionization, where electrons knock out other electrons from sample molecules, creating ions that can then be analyzed based on their mass-to-charge ratio. Photo-ionization is a related process where electromagnetic radiation, like light, causes the ejection of electrons or the dissociation of matter into charged particles. The probabilities and energy thresholds for ionization differ between photo-ionization and charged-particle impact.132