ESR Measurement of Quadrupole Coupling in N(SO3)22−

Abstract

The so‐called second‐order transitions in ESR spectra, which involve a change in both electron and nuclear spin, are sensitive to electric quadrupole coupling. The quadrupole interaction for ¹⁴N in N(SO₃)₂²⁻ was studied by observation of these transitions at 31.5 GHz in single crystals of γ‐irradiated potassium aminedisulfonate. The resulting spectra can be explained assuming the principal axis system of the field‐gradient tensor is the same as the hyperfine coupling tensor. The coupling constants then become $e^2{\mathrm{Qq}}_{\mathrm{x\prime x\prime }}\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}5.2\hspace{0.17em}±\hspace{0.17em}1.4}\mathrm{MHz}$ and $e^2{\mathrm{Qq}}_{\mathrm{y\prime y\prime }}\text{\hspace{0.17em}=\hspace{0.17em}+\hspace{0.17em}3.2\hspace{0.17em}±\hspace{0.17em}1.0}\mathrm{MHz}$ , where the $\mathrm{x\prime }$ and $\mathrm{y\prime }$ principal axes have direction cosines of (0.829, 0, 0.559) and (0, 1.0, 0) in an $\mathrm{a*\; bc}$ axis system.