Minimum energy required to eject an electron out of a neutral atom or molecule in
its
ground state. The
adiabaticionization energy refers to the formation of the molecular ion in its ground vibrational state
and the
vertical ionization energy applies to the transition to the molecular ion without change in geometry.
This quantity was formerly called
ionization potential. The second
ionization energy of an atom is the energy required to eject the second electron from the atom
(energy for the process
).
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1128
