Nuclear Quadrupole Coupling in Polar Molecules

Abstract

The quadrupole moment induced in various ions by the nuclear electric quadrupole moment $Q$ has been recalculated to higher accuracy than in a previous paper. Values are presented for the ratio ${\ensuremath{\gamma}}_{\ensuremath{\infty}}$ of the induced moment to $Q$ for the ${\mathrm{Na}}^{+}$, ${\mathrm{Cl}}^{\ensuremath{-}}$, ${\mathrm{Cu}}^{+}$, ${\mathrm{Rb}}^{+}$, and ${\mathrm{Cs}}^{+}$ ions. These values of ${\ensuremath{\gamma}}_{\ensuremath{\infty}}$ enter into the quadrupole coupling of polar molecules, which is given by $q\ensuremath{\cong}\frac{2e(1+|{\ensuremath{\gamma}}_{\ensuremath{\infty}}|)}{{R}^{3}}$ ($R=\mathrm{internuclear}\mathrm{distance}$) provided that the exchange repulsion of the ions can be neglected. The calculated values of ${\ensuremath{\gamma}}_{\ensuremath{\infty}}$ are of order 10-100, in agreement with experimental evidence from the measured values of $q$ for several polar molecules.