The millimeter wave rotational spectrum of gallium monofluoride (GaF)
has been studied in the 250-300 GHz frequency region. Using a new meth
od of molecular production in a free space cell three rotational trans
itions of (GaF)-Ga-69 and four rotational transitions of (GaF)-Ga-71 i
n the v=0, 1 and 2 vibrational states have been measured. The analysis
including previous measurements on the lower rotational transitions i
n the microwave region yielded an improved and extended set of Dunham
molecular parameters.