Charge neutralization pulse

Surface charge neutralization by a pulsed electron flood was not required for any of the materials, either in the positive or in the negative ion mode. The spectra were carefully calibrated using the exact masses of peaks with known composition, such as those from the source, 69Ga+ at 68.926 amu the substrate, e.g. 56Fe v at 55.935 amu and some siloxane peaks, e.g. (CH3)3Si at 73.047 or (CH3)5Si204 at 147.066 amu. 

Tanaka et al. studied the decay reactions of PVB radical anions produced by electron pulses in MTHF [47]. At low concentration ( < 0.05 base-mol dm - 3) of polymers the decay reaction followed a simple second-order kinetics. The charge neutralization reaction is responsible for the decay curve as is the case of biphenyl radical anions. However, the rate constant of the polymer anions was only a half or one-third of that of the biphenyl anion, because of the small diffusion coefficient of the polymer ion in solution. At high concentration of the polymer, a spike was observed in the time-profile of the PVB anion this was attributed to the retarded geminate recombinations within micro-domains where the polymers were entangled with each other. 

Double pump experiments on an organic charge transfer complex TTF-CA by Iwai and coworkers demonstrated a new class of coherent control on a strongly correlated electron-lattice system [44]. While the amplitude of the coherent oscillation increased linearly with pump fluence for single pump experiments, the amplitude in the double pump experiments with a fixed pulse interval At = T exhibited a strongly super-linear fluence dependence (Fig. 3.16). The striking difference between the single- and double-pulse results indicated a cooperative nature of the photo-induced neutral-ionic transition. 

Pulse Experiments. PELDOR studies of Fremy s salt in 1 1 water glycerol demonstrated that the spatial distribution of these radicals with a 2 — charge was significantly different than for the neutral tempone radical, which was attributed to electrostatic repulsion.43... 

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