The electron-nuclear-double-resonance spectral frequencies of ${}_{}{}^{147}{}_{}{}^{}\mathrm{Sm}_{}^{+3\mathrm{}}{}_{}{}^{}$ and ${}_{}{}^{149}{}_{}{}^{}\mathrm{Sm}_{}^{+3\mathrm{}}{}_{}{}^{}$ ions dilutely substituted at ${\mathrm{La}}^{+3\mathrm{}}$ ion sites in La${\mathrm{Cl}}_3$ single crystals at 2.07 °K have been measured. The experimental results for both nuclides have been summarized by giving values of the parameters in a spin Hamiltonian for a least-squares best fit to the measurements. The values of (a) nuclear $g$ factors and nuclear magnetic-dipole moments for both nuclides, of (b) $〈r^{-3\mathrm{}}〉$ for the $f$ electron-nuclear distance in ${\mathrm{Sm}}^{+3\mathrm{}}$, of (c) ratios of nuclear magnetic-dipole moments and (d) ratios of nuclear electric-quadrupole moments for the two nuclides, and of (e) the ratio of the crystal-field shielding and antishielding factors $1-{\sigma }_2$ and $1-{\gamma }_{\infty }$ for ${\mathrm{Sm}}^{+3\mathrm{}}$ in La${\mathrm{Cl}}_2$, which are obtainable from these measurements, are discussed and tabulated.

• Received 30 August 1971

DOI:https://doi.org/10.1103/PhysRevB.5.3387