Nuclear hyperfine coupling constants of aluminium monoiodide determined by Fourier-transform microwave spectroscopy

The ground-state rotational spectrum of 27Al127I has been investigated by Fourier-transform microwave spectroscopy. AlI was generated by reaction of laser-ablated aluminium vapour with methyl iodide. The rotational constant (B0), nuclear quadrupole coupling constants ( χ aa Al , χ aa I ) and the nuclear spin-rotation constant of iodine ( C bb I ) have been re-determined with high precision. The nuclear spin-rotation constant of aluminium ( C bb Al ) , the nuclear spin–spin constants ( D aa Al , I , δ Al , I ) and the dependence of the coupling constant χ aa I on J ( χ J I ) were determined. D aa Al , I and δAl,I agree with calculated values and χ J I is consistent in sign and magnitude with the known dependence of χ aa I on vibrational state.