Pseudoquadrupole Shift and Asymmetric Line Broadening of Recoilless Nuclear Resonance Spectra

Abstract

Large, temperature-dependent line shifts and asymmetric line broadenings have been observed in recoilless nuclear resonance spectra of several rare-earth compounds. The shifts are shown to be due to a second-order magnetic hyperfine interaction, while the broadenings are partially attributed to electron spin-spin relaxation. A detailed theoretical analysis of the line shifts is presented and shown to agree well with experimental observations in Tm${\mathrm{Cl}}_3$·6${\mathrm{H}}_2$O.