Electronicg-Factor and the Structure ofF-Centers

A study is made of the small electronic $g$-factor shifts observed in complex paramagnetic substances. In most cases there is a simple connection between the contribution of a given ion or atom to $\Delta g$ and the anisotropic part of the magnetic hyperfine interaction of its nucleus with the electron. This connection is useful now that a double-spin-resonance technique developed recently by Feher can give experimental values for such hyperfine interaction constants.