Thermal ionization is a process where atoms or molecules gain enough thermal energy to lose electrons, resulting in the formation of ions. This typically occurs at high temperatures, where the kinetic energy of particles is sufficient to overcome the binding energy of electrons. It is commonly used in mass spectrometry and other analytical techniques to study the composition of materials. In thermal ionization, elements with low ionization energies, such as alkali metals, are more easily ionized. The process can be enhanced by using a thermal ionization mass spectrometer, which allows for precise measurements of isotopic ratios and elemental concentrations in various samples.