Electric quadrupole moments of radioactive Pt isotopes

Abstract

Nuclear orientation experiments were performed on¹⁸⁹Pt (I^π=3/2⁻; T_1/2=11 h),¹⁹¹pt (I^π=3/2⁻; T_1/2=2.8 d) and^195mpt^π=3/2⁻; T_1/2=4.0 d) in an Os single crystal at temperatures down to 10 mK. Preliminary results for the quadrupole splitting ν_o=e²qQ/h are +48 (9), +39 (6), and −87 (12) MHz for¹⁸⁹ptOs,¹⁹¹ptOs, and¹⁹⁵mptOs, respectively. Preliminary results for the quadrupole moments are −0.8 (4), −0.6 (3), and +1.4 (7) b for¹⁸⁹pt,¹⁹¹pt, and¹⁹⁵mpt, respectively. In addition, the quadrupole subresonance structure of¹⁸⁹pt and¹⁹¹pt in Fe was measured with quadrupole-interaction resolved NMR-ON spectroscopy. The results for the magnetic hyperfine splitting ν_M=¦gμ_NB_HF/h¦ and ν_Q are:¹⁸⁹ptFe: ν_M=277.9 (1) MHz; ν_Q=+1.39 (5) MHz.¹⁹¹ptFe: ν_M=320.17 (3) MHZ; ν_Q=+1.39 (3) MHz. The ratio of the quadrupole moments of¹⁹¹pt and¹⁸⁹pt is deduced to be Q (¹⁹¹Pt/Q^l89pt)=+1.00 (4). The negative quadrupole moments of¹⁸⁹pt and¹⁹¹pt indicate a predominantly oblate shape of the ground states.