Photodetachment from cluster ions

Negative oxygen ions in wet tetramethylsilane were found to become hydrated (Balakin et al, 1993). This effect manifests itself in a decrease of the ion mobility and in a shift of the photodetachment threshold, lion(liq), of +0.4 eV due to an increase of I P I. At low water concentrations, the solvation process probably occurs in steps until an equilibrium is established  

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This is just what has been done with Ag2. A sputtering source followed by a phase-space compressor chamber provided a beam of cooled negative cluster ions of many sizes. From these, the dimers were selected, accumulated in a quadrupole trap, and photodetached with a femtosecond, titanium-sapphire laser. After photodetachment by a 60-fs pulse, the neutral dimers oscillate, causing corresponding oscillations in the ionization cross section, in turn generating the oscillations that dominate the intensity pattern in Fig. 11. This is a simple phenomenon, yielding in a simple way the... 

An analj is of the interactions of ions with ligands leads to valuable information which is difficult to obtain otherwise. Important data for resolving the dynamical structure of the protonated methane cation CHs arises from the infra-red spectra of CH5 (H2)n [45,61]. The topology of shells is projected on the properties of bare ions. The process of the consecutive electron photodetachment from the central anion indicates the existence of the well developed shell structure of complexes. The theoretically predicted electronic affinities for O AXn clusters calculated for theoretical structures of complexes agree with the known measured values (Table 3) [62,63]. The ionization potential of CHa Arn clusters is little... 

Note that solvated electrons can also be produced by photodetachment of electrons from certain anions or photoionization of molecules using UV excitation.Then the mechanism of metal ion reduction is expected to be quite similar to the radiolytic processes of Figures 2a, 2b and 2c. However, the matrices used as cluster hosts are generally not transparent to light, and the reduction is often restricted to the surface. 

Negatively charged, mass-selected silver trimers are caught in a linear quadrupole trap. There, their excess electrons are photodetached with a pulse of radiation in the range of 400 nm, with a duration of nearly 100 fs. The neutrals prepared in this way would remain in the trap for nanoseconds or even milliseconds. However, a second ultrashort pulse of the same radiation, intense enough to induce TPI of the clusters, is directed into the trap after a preselected delay, allowing the neutral to carry out internal motion, from a small fraction of a vibration to many vibrations. The positive ions generated in this way, are then mass-analyzed and collected. Thus, the yield of... 

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