New f-values in neutral lead obtained by time-resolved laser spectroscopy, and astrophysical applications

Abstract

Natural radiative lifetimes have been measured for three odd-parity levels of neutral lead using time-resolved UV laser-induced fluorescence from a laser-produced plasma. These new lifetimes, as well as additional recent values obtained by laser spectroscopy, combined with theoretical branching ratios deduced from a relativistic Hartree—Fock calculation taking core polarization effects into account, have allowed the deduction of a new set of accurate f-values of astrophysical interest. Using the new lifetime value for 6p7s (1/2, 1/2)°0, a refined value of the lead abundance in the solar photosphere is deduced: APb= 2.00±0.06 on the usual logarithmic scale, allowing the resolution of the long-standing discrepancy previously observed between the solar photosphere and meteorites.