Spectral simulation and interpretation of LiZn and LiCd blue-green emission

Excited LiZn and LiCd molecules are produced in a photochemical reaction between Li2(C 1Πu) molecules and zinc or cadmium atoms. Changes in shape of the blue-green emission are observed by increasing the total vapor pressure in the heat pipe oven. Quantum mechanical spectral simulations are carried out for the relevant 2 2Π → X 2Σ+ transitions. Both bound-bound and bound-free types of transitions are found to play an important role in the overall blue-green spectra. For high collision frequencies (high total vapor pressure) the simulated spectra show very good agreement with observations if a thermal distribution in the 2 2Π states is assumed. In this case bound-bound transitions are dominant. The results for low collision frequencies indicate that the nascent distribution is non-Boltzmann and that bound-free transitions are dominant. (orig.)