energy level

of a free atom, ion or molecule
synonym: energy state
https://doi.org/10.1351/goldbook.08246
Set of one or more stationary quantum states of a free atom, ion, or molecule having a particular internal energy.
Note:
SI unit: \(\pu{J}\). Common unit: electron volt, symbol \(\pu{eV}\), where \(\pu{1 eV} = \pu{1.602176634E-19 J}\). Energy levels are also expressed as \(\pu{kJ mol-1}\).
Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 658 [Terms] [Paper]