Fotóionizaci

Fotóionizaci is a physical process where an atom or molecule absorbs one or more photons, leading to the ejection of one or more electrons. This absorption of energy excites the electron to a higher energy level, and if the photon's energy exceeds the binding energy of the electron, it can overcome the electrostatic attraction to the nucleus and escape. The process is fundamentally an ionization event driven by light.

The minimum energy required for fotóionizaci is determined by the ionization potential of the species involved. For a single photon to cause ionization, its energy must be at least equal to the ionization potential. This is often expressed in terms of electronvolts (eV) or the wavelength of the light. In cases where the photon energy is less than the ionization potential, a process called multiphoton ionization can occur, where the absorption of multiple photons sequentially provides enough energy to liberate an electron.

Fotóionizaci is a crucial phenomenon in various fields. In astrophysics, it plays a role in the ionization of interstellar gas and the atmospheres of stars and planets. In spectroscopy, it is the basis for techniques like photoionization spectroscopy, used to study atomic and molecular energy levels. It is also relevant in the study of radiation damage and in the development of photodetectors and other optical devices. The probability of fotóionizaci depends on the photon's energy, the type of atom or molecule, and the polarization of the light.