High-spin states of ${}^{143}\mathrm{Nd}$ have been studied using $\gamma -\gamma$ and $\gamma$-conversion electron coincidences. The measurement of 16 new transitions and 8 new conversion coefficients allow revision of the high-spin portion of the level scheme and the determination of parities of six levels for the first time. While the yrast states up to $J=43/2\mathrm{}$ can be described using the weak coupling of an $f_{7/2}$ neutron to the ${}^{142}\mathrm{Nd}$ core nucleus, the new experimental results suggest that weak coupling breaks down above $J=43/2.\mathrm{}$ This behavior may signal that the closed $N=82\mathrm{}$ neutron shell of ${}^{142}\mathrm{Nd}$ is broken above $J=16.\mathrm{}$

• Received 20 January 1998

DOI:https://doi.org/10.1103/PhysRevC.58.826