Rotational structure in multiply excited atoms

An analysis based on intrinsic anisotropic states exposed to rotation explains why approximate rotorlike energy spectra appear in multiply excited atoms. For intrashell excited atoms, unlike molecules and nuclei, the rotor structure is not associated with rotational kinetic energy. Close examination of a general argument from nuclear physics shows that the rotorlike series are due to the behavior of wave function overlaps and matrix elements of the electron-electron repulsion between rotated anisotropic states.