Isotope shift in erbium I by laser-atomic-beam spectroscopy.

Abstract

High-resolution laser spectroscopy has been performed on an atomic beam of natural erbium isotopes. The isotope shift in the 582.7 nm transitions [${4\mathrm{f}}^{12}$${6\mathrm{s}}^{2}$(${\mathrm{}}^{3}$${\mathrm{H}}_{6}$)\ensuremath{\rightarrow}${4\mathrm{f}}^{12}$(${\mathrm{}}^{3}$${\mathrm{H}}_{6}$)66(${\mathrm{}}^{3}$${\mathrm{P}}_{1}^{0}$)J=7] for the pairs of $^{162}$,164,166,167,168,170Er I was obtained with an accuracy of about 4 MHz. Relative changes of mean-square nuclear charge radii \ensuremath{\delta}〈${r}^{2}$〉 for these isotopes were thus deduced. The isotope shift in $^{167}\mathrm{Er}$, obtained from the well-resolved hyperfine components, shows similar even-odd staggering effect in \ensuremath{\delta}〈${r}^{2}$〉 found in the nearby elements.