Hyperfine splitting and isotope shift in the optical transition 4f(7)6s(2)S-8(7/2) -> 4f(7)6s6p P-6(5/2) of Eu-151,Eu-153,Eu-155 isotopes and electromagnetic moments of Eu-155

The laser-induced resonance fluorescence in an atomic beam was used in orde r to measure the hyperfine splitting of the 4f(7)6s(2) S-8(7/2) and 4f(7)6s 6p P-6(5/2) levels in Eu-151,Eu-153,Eu-155 isotopes. The hfs constants A an d B of the unstable Eu-155 were determined for the first time: A(exp)(155, S-8(7/2)) = -8.78(3) MHz, A(exp)(155, P-6(5/2)) = -261.68(11) MHz and B-exp (155, P-6(5/2)) = -951(1) MHz. With these data and after corrections for se cond-order hyperfine structure perturbations the nuclear moments of Eu-155 were deduced: mu(155) = 1.520(2) n.m. and Q(5)(155) = 2.494(20) b. In addit ion new and more precise values of the hfs constants of the excited state f or the stable Eu-151,Eu-153 were obtained. They are as follows: A(exp)(151, P-6(5/2)) = -591.92(9) MHz, B-exp(151, P-6(5/2)) = -354.58(97) MHz and A(e xp)(153, P-6(5/2)) = -263.19(8) MHz, B-exp(153, P-6(5/2)) = -922.07(79) MHz . The hyperfine anomalies (151)Delta(153) = 0.74(4)% and (153)Delta(155) = 0.27(34)% were extracted from the corrected hfs constants.