The hyperfine structure in the $J=3\mathrm{}\leftarrow J=2\mathrm{}$ rotational transition of the diatomic AgI molecule in its vibrational states $v=0,1,2,3, \mathrm{and} 4$ of the electronic ground state has been studied in the frequency region of 8 GHz. The variation of the nuclear quadrupole coupling of the iodine nucleus with vibrational state in ${}_{}{}^{107}{}_{}{}^{}\mathrm{Ag}$${}_{}{}^{127}{}_{}{}^{}\mathrm{I}$ and ${}_{}{}^{109}{}_{}{}^{}\mathrm{Ag}$${}_{}{}^{127}{}_{}{}^{}\mathrm{I}$ has been investigated and the nuclear quadrupole coupling constant $e{q}_{v}Q$ can be expressed as $e{q}_{v}Q\left({}_{}{}^{127}{}_{}{}^{}I\right)=-1061.37\mathrm{}\left(11\right)-[2.13(5\left)\right](v+\frac{1}{2})$ MHz. Stark-effect measurements have been carried out on ${}_{}{}^{107}{}_{}{}^{}\mathrm{Ag}$${}_{}{}^{127}{}_{}{}^{}\mathrm{I}$ in its electronic and vibrational ground state. A least-squares fit of the Stark shifts at various electric fields gives the electric dipole moment of AgI as $\left|{\mu }_0\mathrm{}\right|=4.550\left(50\mathrm{}\right)\mathrm{}$ D.

• Received 24 October 1983

DOI:https://doi.org/10.1103/PhysRevA.29.1889