Spin-Orbit Splittings in Nuclear Shell Model

All available data (mostly from "stripping reactions") on locations of nuclear shell-model states are analyzed to determine energy splittings of spin-orbit doublets, and the systematics is studied. The expected ($2l+1$) dependence of the splitting is roughly corroborated, but the splitting is considerably larger than expected when the two levels are in different major shells. The mass dependence of the splitting is somewhat stronger than the expected proportionality to $A^{-\frac{1}{3}}$. Applications to "reduced mass" questions, and to the location of unknown levels are discussed.