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The decay dynamics of photoexcited rare gas cluster ions J. Chem. Phys. 111, 959 (1999); 10.1063/1.479378 A selected-ion-flow-drift-tube study of charge transfer processes between atomic, molecular, and dimer ion projectiles and polyatomic molecules ethane, propane, and n-butane Kinetics associated with the decay of the low-lying excited states of xenon is investigated in a density range 2.S X 10 18 to 2.S X 10 20 atoms cm -3 (pressure range between 10 4 and 10 6 Pa). Three different experiments are performed, i.e., two-photon excitation of 6p atomic states or ot molecular states, VUV one-photon excitation of the 6s[ 3/2] I and 6s' [ 112] I atomic states, and laser probing of intermediate transient species. The basic experimental data are the timeresolved second continuum excimer fluorescence at -173 nm and the photoionization current. It is found that all excitation decays through 6s[3/2] lor 6s[3/2Jz with a branching ratio 9/1. Part ofthe 6s[3/2] I species (70%) decay subsequently via the 6s[3/2Jz level. The effectiveness of these atomic intermediate steps is directly demonstrated by the transient laser probing. This result, the time analysis, and the discussion allow to set a clear basis to the involved processes and to rule out part of the models proposed in the literature. In particular, the hypothesis of infrared decay from attractive high-lying molecular states to the lowest lying excimer states 0: /6s[3/2] I and luOu-/6s[3/2]z is rejected. The data treatment, with the help of 2 or 2 X 2 exponential formula depending on density, is discussed. It takes into account the instrumental response so that kinetics information is reached down to the nanosecond range. In particular, the 0:, v::::::0/6s[3/2] I relaxed excimer lifetime is found to be 4.S(5) ns, and that ofthe lu,O; /6s[3/2Jz state 103(2)ns.

Line identifications in the beam-foil spectrum of boron. H. G. Berry (Depart-