The Calculation of Internal Conversion Coefficients

Abstract

We treat the internal conversion of nuclear $\ensuremath{\gamma}$-rays by methods suited especially to the cases of the artificially radioactive elements. The paper is divided into five parts: Section 1 discusses the radiative transitions in nuclei of middle atomic weights, where one may expect large angular momentum changes and low energy of excitation; in Section 2 we consider the selection rules for the various types of nuclear radiation, and the conditions on their strictness; in Section 3 we examine the choice of potentials for the representation of the multipole fields; Section 4 contains calculations leading to a nonrelativistic formula for the conversion of electric multipole radiation of any order, applicable for $Z<40$ and $\ensuremath{\gamma}$-ray $\ensuremath{\ll}m{c}^{2}$; and very simple relativistic formulae are derived, good for high $\ensuremath{\gamma}$-ray energy but restricted to low binding, $Z<30$, for both magnetic and electric multipoles of any order. We summarize the qualitative behavior of the formulae in a conclusion.