Specific mass shift of potassium 5P_(1/2) state

摘要

We have measured the isotope shift between ~(41)K and ~(39)K in the 4s_(1/2) -> 5p_(1/2) transition at 405 nm using saturation spectroscopy. Our measured isotope shift is 456.1 +- 0.8 MHz, implying a residual isotope shift (sum of specific mass shift and field shift) of -52.7 +- 0.8 MHz. We deduce a specific mass shift of -40 +- 5 MHz, which would imply that the 5p_(1/2) state has a considerably larger specific mass shift than the 4p_(1/2) state. We have in addition measured the 5p_(1/2) hyperfine splitting for ~(41)K.