Abstract
Relative integrated intensities for the 40 bands of the (B to X) system of lanthanum oxide have been measured by the technique of photographic photometry. A Morse model is employed to compute the Franck-Condon factors and the r-centroids. The variation of the electronic transition moment Re(r) with the internuclear separation r is found to be R/sub /e(r)=const*exp(1.98r) in the range 1.643AA<r<1.995AA. Smoothed relative band strengths are derived for the 27 bands. Effective vibrational temperature of the source is determined.