Calculation of magnetic hyperfine constant of P31

Abstract

The results of different kinds of calculations, which use the concept of spin polarization, all predict a negative sign of the magnetic hyperfine constant of the S4 ground state of P31 in contradiction with the sign deduced by Lambert and Pipkin from an optical pumping experiment. This result means that either an error in experimental sign has been made or that the first serious breakdown of the exchange polarization model has been found. © 1964 The American Physical Society.