inner orbital X-ray emission spectra
X-ray spectral lines generated by the transition of electrons between 'inner orbitals'. The term 'inner orbital' serves to designate the sharp, not degenerate electronic levels of atoms in a solid and therefore is a general term for all orbitals except the valence band.
PAC, 1983, 55, 2023. 'Nomenclature, symbols and units recommended for in situ microanalysis (Provisional)' on page 2026 (