L3Conversion of the 2.38-keV Isomer inNb90

Abstract
The 3.8% decrease in half-life of the 2.38-keV Nb90m isomer when Nb is converted from metal to a fluoride complex is one of the largest reported chemical effecs on the internal conversion process. We present experimental and theoretical evidence that this effect is not due, as had been conjectured, to the "switching off" of L3 conversion through increased L3 binding energy.