The resulting spectra are known as radio-frequency (rf) spectra, or microwave spectra they are observed typically in the frequency range from 10 6 to 10 11 hertz. Transitions also can occur in atoms, molecules, and ions between high-energy electronic states near the ionization limit. Such transitions either can be spontaneous or can be induced by the application of appropriate external electromagnetic fields at the resonant frequencies. Molecules also undergo transitions between rotational and vibrational states. Separations between levels differing only in the relative orientation of the magnetic field of the nucleus and electron range typically from 10 6 hertz to 10 10 hertz.Ītoms, ions, and molecules can make transitions from one state to another state that differs in energy because of one or more of these magnetic effects. This additional structure of an atom’s levels or of spectral lines caused by the magnetic properties of its nucleus is called magnetic hyperfine structure. The levels will have different energies, depending on the relative orientation of the nucleus and the magnetic field produced by the surrounding electrons. As a result, an atomic level that consists of several states having the same energy when the nucleus is nonmagnetic may be split into several closely spaced levels when the nucleus has a magnetic moment. Nuclei of atoms often have intrinsic angular momentum ( spin) and magnetic moments because of the motions and intrinsic magnetic moments of their constituents, and the interactions of nuclei with the magnetic fields of the circulating electrons affect the electron energy states. Energy differences between levels having different energies because of magnetic interactions vary from less than 10 7 hertz to more than 10 13 hertz, being generally greater for heavy atoms. Other, usually weaker, magnetic interactions within the atom exist between the magnetic moments of different electrons and between the magnetic moment of each electron and the orbital motions of others. The spin-orbit interaction has been discussed above ( see Fine and hyperfine structure of spectra).
Electrons and nuclei have magnetic properties in addition to these electrostatic properties. The energy states of atoms, ions, molecules, and other particles are determined primarily by the mutual attraction of the electrons and the nucleus and by the mutual repulsion of the electrons. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!.Learn about the major environmental problems facing our planet and what can be done about them! Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.