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: \(^{2}\rm{P}_{1/2}\) denotes an atomic state of multiplicity 2 (doublet), electron orbital angular momentum quantum number \(L=1\), and orbital plus spin angular momentum quantum number \(J=\frac{1}{2}\).