Search for Extended-Lifetime Optically Excited Laser Media. Final Report

摘要

Studies of optically excited cryogenic rare-gas fluorine solutions indicate an efficient two-step, one-photon channel into several excited dimer and trimer states. The excitation is sensitive to the pump wavelength with respect to the excitation efficiency as well as the type of excited state obtained. The excited states radiate on several B-X, C-A, D-X dimer and GAMMA-GAMMA trimer transitions. The trimer transitions were assigned to (6 exp 2 GAMMA - 1,2 exp 2 GAMMA) and (4 exp 2 GAMMA - 1,2 exp 2 GAMMA) where the upper state can be formed by a clustering reaction involving the D and B state of the dimer, respectively. In pure Xe(F sub 2 ) solutions, the stability of the D and B dimer states is questionable. Theoretical Xe sub 2 F* potential energy curves reported by Huestis et al indicate that, at high Xe densities, these dimer states should collapse into the 6 exp 2 GAMMA and 4 exp 2 GAMMA Xe sub 2 F* trimer states, respectively. Lifetimes as great as 50 nsec in the liquid environment have been observed. All emissions are observed red-shifted with respect to the gas phase values, and shifts of up to 0.9 eV in magnitude have been observed for the D-X transition in XeF. (ERA citation 09:023154)