HIGH-RESOLUTION INFRARED-EMISSION SPECTRA OF GAH AND GAD

The high resolution infrared emission spectra of gallium hydride and g allium deuteride have been recorded with a Fourier transform spectrome ter. There were 1045 lines observed including those from the v = 1 --> 0 to v = 7 --> 6 bands for the (GaD)-Ga-69 and (GaD)-Ga-71 species an d v = 1 --> 0 to v = 4 --> 3 bands for the (GaH)-Ga-69 and (GaH)-Ga-71 species. Dunham Y(ij)'s for each isotopomer were obtained by fitting the data set of each isotopomer separately to the Dunham energy levels of the X1SIGMA+ electronic ground state. The mass-reduced Dunham U(ij )'s were determined using two independent methods. In the first fit th e U(ij)'s constants were determined by the traditional method where al l the constants were treated as adjustable parameters and determined s tatistically. In the second fit the U(ij)'s which satisfied the condit ion j < 2 were treated as adjustable parameters and the remaining cons tants were fixed by constraints imposed by the Dunham model. In order to predict the positions of transitions with v's and J's much higher t han those observed the entire data set was fit directly to the eigenva lues of the Schrodinger equation containing a parameterized internucle ar potential energy function.