Isotope shifts and fine structures ofLi6,7Dlines and determination of the relative nuclear charge radius

Abstract

The $^{6,7}\mathrm{Li}\phantom{\rule{0.3em}{0ex}}D$ lines were excited using an electro-optically modulated cw dye laser that intersected an atomic beam. Fluorescence was recorded as the laser was scanned across the resonance. Hence each transition was multiply excited allowing for calibration of the frequency scan. The $^{6,7}\mathrm{Li}\phantom{\rule{0.3em}{0ex}}2P$ fine structures were found to be $10\phantom{\rule{0.2em}{0ex}}052.964\ifmmode\pm\else\textpm\fi{}0.050$ and $10\phantom{\rule{0.2em}{0ex}}053.119\ifmmode\pm\else\textpm\fi{}0.058\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$. The $D1$ and $D2$ isotope shifts were determined to be $10\phantom{\rule{0.2em}{0ex}}534.039\ifmmode\pm\else\textpm\fi{}0.070$ and $10\phantom{\rule{0.2em}{0ex}}534.194\ifmmode\pm\else\textpm\fi{}0.104\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$. The latter imply values for the $^{6,7}\mathrm{Li}$ relative nuclear charge radius that are within $20\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\phantom{\rule{0.3em}{0ex}}\mathrm{fm}$ of each other, which is consistent with the estimated uncertainties.