The study of the hyperfine structure in the optical spectrum of LuI for the
transition between the levels of the ground term D-2(3/2) and the excited
term F-4(3/2) is reported. The method of laser resonance fluorescent in an
atomic beam was used:The magnetic dipole and electric quadrupole constants
of hyperfine splitting for the Lu-175 and Lu-176 isotopes were measured. Th
e hyperfine magnetic anomaly for the F-4(3/2) level was found to be 0.74(15
)%.