Magnetic Dipole and Electric Quadrupole Moments of the First2+State ofSm154

The hyperfine interactions of the first excited $2^{+}$ state of ${\mathrm{Sm}}^{154}$ have been measured in Sm${\mathrm{Cl}}_3$·6${\mathrm{H}}_2$O and SmIG at 4.2°K, using the Mössbauer effect following Coulomb excitation. The results in Sm${\mathrm{Cl}}_3$·6${\mathrm{H}}_2$O have been used to determine the magnetic dipole and electric quadrupole moments ${\mu }^{154}=(0.778\mathrm{}\pm 0.036){\mu }_N$ and $Q^{154}\mathrm{}(1-R)=-1.33\mathrm{}\pm 0.46$ b, respectively. ${\mu }^{154}$ has been used to determine $H_{\mathrm{eff}}=3.04\mathrm{}\pm 0.12$ MG in SmIG at 4.2°K. This value for $H_{\mathrm{eff}}$ (SmIG) agrees with the value used by Atzmony et al. to measure ${g_R}^{152}$ in SmIG; thus their value for ${g_R}^{152}$ is confirmed. An improved technique for using the Mössbauer effect following Coulomb excitation is reported.