The PERMANENT ELECTRIC DIPOLE MOMENT AND HYPERFINE INTERACTION IN GOLD SULFIDE, AuS

The bonding and electrostatic properties of gold containing molecules are highly influenced by the large relativistic and electron correlation effects.footnote{P. Pyykko; textit {Angew Chem. Int[43] }, {textbf{4412}},(2004).} Here we report on the electricpermanent dipole moment measurement and hyperfine interaction analysis of the $^{2}$$Delta$$_{3/2}$-$^{2}$$Pi$$_{3/2}$ and $^{2}$$Delta$$_{5/2}$-$^{2}$$Pi$$_{3/2}$ bands of AuS. A cold molecular beam sample of gold sulfide was generated using a supersonic laser ablation source. The electronic bands were recorded at high resolution (35 MHz, FWHM) using laser excitation spectroscopy both field-free and in the presence of a static electric field. The observed hyperfine spectral features were assigned and a set of spectroscopic parameters for the $^{2}$$Delta$ and $^{2}$$Pi$ states were obtained. The Stark induced shifts of selected low-rotational features were analyzed to determine the permanent electric dipole moments in both the ground and excited states