Observation of the lowest triplet transitions 3Σg+-3Σu+ in Na2 and K2

We report here the observation and definite identification of the lowest triplet transition 3Σ+g–3Σ+u in Na2 and K2. The identification of these bands is based upon direct comparison of K2 absorption, thermal emission, and laser-induced fluorescence, and Na2 laser-induced fluorescence, with spectra calculated from recent, accurate, ab initio potential curves. These data also serve as a sensitive check on the accuracy of these potentials.