Progress at NIST in measuring the D-lines of Li isotopes using an optical frequency synthesizer

摘要

Abstract: Precise spectroscopic experiments with light atoms can provide information about nuclear properties that arenvery difficult to obtain in electron scattering experiments. For example, relative nuclear radii of low-Z isotopes can be de-ntermined accurately from isotope shifts. Theory has attained sufficient accuracy to study exotic, short-lived halo nuclei byninterpreting precise spectroscopic measurements. However, serious inconsistencies remain in the measured isotope shiftsnfor the D1 and D2 lines of the stable isotopes (n6Li and 7Li). The latest experiments, within the last decade, are in strongndisagreement with each other and with theory. We report on the progress of a new experiment at the National Institute ofnStandards and Technology (NIST) to measure these lithium D lines using an optical frequency comb. A preliminary resultnfor the splitting isotope shift (SIS) is presented.