The Pure Rotational Spectrum, Geometry, and Hyperfine Constants of Hafnium Monosulfide, HfS

The pure rotational spectra of seven isotopomers of hafnium monosulfide have been measured for several vibrational states. For the most abundant isotopomer, 180Hf32S, the J=1 - 0, J=2 - 1, and J=3 - 2 transitions were recorded up to the sixth vibrationally excited state. The constants Y01, Y02, Y11, Y21, and Y31 were determined via a multi-isotopomer fit to a Dunham-type expression. In the process of fitting the data it was necessary to include Born–Oppenheimer breakdown correction terms. The equilibrium internuclear distance has been evaluated. For both the 177Hf32S and 179Hf32S isotopomers, nuclear hyperfine structure due to the hafnium nucleus was observed and notably large Hf nuclear quadrupole coupling constants, eQq, were determined. [Copyright &y& Elsevier]