Institute for Theoretical Atomic, Molecular and Optical Physics between AMO theory and experiment and promoting AMO theory within the general physics community. It has been involved in some capacity in most of the National Research Council target areas, i.e. precision measurements and tests of fundamental laws, ultracold physics, the development and application of ultra-intense, short wavelength light sources, ultra-fast quantum control of atoms, molecules and electrons, nanoscience, and quantum information science. The Institute is sponsored by the National Science Foundation, the Smithsonian Institution, the Center for Astrophysics and Harvard University. The Armstrong Report in 1987 on "The State of Theoretical Atomic, Molecular and Optical Sciences in the United
Atomic radii of the elements (data page) Atomic radii of the elements (data page) The atomic radius of a chemical element is the distance from the centre of the nucleus to the outermost shell of the electron. Since the boundary is not a well-defined physical entity, there are various non-equivalent definitions of atomic radius. Depending on the definition, the term may apply only to isolated atoms, or also to atoms in condensed matter, covalently bound in molecules, or in ionized and excited states; and its value may be obtained through experimental measurements, or computed from theoretical models. Under some definitions, the value of the radius may depend