Analysis of the isotope shifts and hyperfine structure in the 3 988 Å (6s6p 1 P 1↔6s 2 1 S 0) YbI line

High-resolution laser spectroscopy using a pulsed dye-laser acting on a collimated atomic beam has been used to determine the isotope shifts in the 3 988 Å YbI line. The following results have been obtained:Δσ(176, 174)=?509(4)MHz,Δσ (174, 173)=?291(10) MHz,Δσ(174, 172)=?530(4) MHz,Δσ(172, 171)=?414(5) MHz andΔσ(172, 170)= ?665(10) MHz. The sign of the magnetic dipole interaction constant in the¹ P ₁ state for¹⁷¹Yb is found to be negative,a(¹ P ₁, 171)=?213.4(3.0) MHz. The electric quadrupole interaction constant for¹⁷³Yb in the¹ P ₁ state is found to beb(¹ P ₁, 173)=605(20) MHz.