Isotope shift of 3 × 10^5-yr ^202Pb in the 6p^2 ³P_0−6p7s ³P1° 2833-nm resonance line

Abstract

The isotope shift in the 283.3-nm resonance line of mass-separated radioactive 202Pb was measured by absorption spectroscopy with the use of our 9.1-m focal-length Czerny–Turner spectrometer. The value of the shift, relative to 208Pb, is −208(3) × 10−3 cm−1. A signal-averaging scanning technique was used to record the spectrum. Isotonic comparisons with the relative isotope shifts in mercury and thallium indicate a possible effect on the isotope shift of the unpaired proton in thallium.