ISOTOPE SHIFTS OF KX RAYS AND VARIATIONS OF NUCLEAR CHARGE RADII

The electronic Kα1 isotope shifts have been studied for the following sets of isotopes: Sn116-124, Nd144-150, Sm148-154, Gd155-156-160, W182-184-186, Hg200-204, and Pb206-208. With the help of a curved-crystal spectrometer in the Cauchois geometry the relative wavelengths of fluorescently excited x rays for two enriched isotope samples were measured to a precision of 10-7. The observed shifts, corrected for the normal and specific mass shifts, were compared with calculated shifts, taking into account the volume effect (adjusted for the dynamic quadrupole interaction), screening by the transition electron, and a term arising from the anomalous magnetic moment. The anomalies previously observed in the optical and muonic shifts are established with good accuracy by the present experiments. © 1968 The American Physical Society.