Inhibition of Magnetic Dipole Radiation and the Identification ofT=1States in Light, Self-Conjugate Nuclei

Abstract

The effects of Coulomb impurities on the inhibition rule of Morpurgo for $\ensuremath{\Delta}T=0$, $M1$ transitions in light ($A<~20$), self-conjugate nuclei are discussed and a comparison is made between Morpurgo's rule and the experimentally known $M1$ transition strengths. An upper limit to the average inhibition of \ensuremath{\sim}10 is indicated by the experimental evidence. There are no known $\ensuremath{\Delta}T=0$, $M1$ transitions in light, self-conjugate nuclei with strengths greater than 0.1 Weisskopf unit. The work of Morpurgo is shown to lead to $J$-dependent lower limits of the order of $0.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}A(A+2)$ Weisskopf units for the matrix elements of $\ensuremath{\Delta}T=0$, $M1$ transitions in self-conjugate nuclei. These limits are invoked to assign isotopic spin to several levels in ${\mathrm{B}}^{10}$, ${\mathrm{N}}^{14}$, and ${\mathrm{F}}^{18}$.