term symbols

https://doi.org/10.1351/goldbook.T06277
Symbols characterizing the states of atoms and molecules in terms of multiplicity, symmetry of the total electronic wavefunction, and sometimes total (orbital + spin)
angular momentum
. Examples: 2P1/2 denotes an atomic state of multiplicity 2 (doublet), electron orbital
angular momentum
quantum number L=1, and orbital plus spin
angular momentum
quantum number J=12.
Source:
Green Book, 2nd ed., p. 28 [Terms] [Book]