Observation of pure quadrupole resonance in zinc metal

We report the first observation of nuclear quadrupole resonance (NQR) in Zn metal. A resonance line, which under the assumption of axial symmetry (η=0) corresponds to the $\text{|M| =}\text{3}\text{2}\text{?}\text{5}\text{2}$ transition in the $\text{I =}\text{5}\text{2}$ ground state of ⁶⁷Zn, has been found at v = 4.086(2) MHz at 4.2K. This yields (for η=0) a quadrupole coupling constant of $\text{e}{}^2\text{qQ}\text{h}\text{= 13.620(8)}$MHz, which is the most accurate value currently available.