TRIPLET-STATE BOUND-FREE TRANSITIONS OF ALKALI DIMERS (NA-2, K-2, ANDRB-2) BY ELECTRON-BEAM EXCITATION

Amplified spontaneous emissions (ASE's) of the Na-2 violet, K-2 yellow , and Rb-2 orange diffuse bands, which are potentially important in th e development of continuously tunable high-pow er laser sources, were observed from electron-beam-excited mixtures of Na-Na-2, K-K-2, or Rb- Rb-2 vapor with argon buffer gas, The continuum spectra centered at 43 6, 574, and 604 nm were attributed to triplet-triplet Na-2, K-2, and R b-2 2(3)Pi(0)--> a(3)Sigma(u)(+) bound-free transitions, respectively. The dissociative recombination reaction of Na-3(+), K-3(+), or Rb-3() is discussed as an efficient formation process of the upper states i n the present electron beam pumping experiments.