Electron photodetachment, equation

The direct photoexcitation of water molecules by ultrashort laser pulses is used for the investigation of primary events occurring from 10 s (thermal orientation of water molecules and ultrafast proton transfer) to 10" s (primary reactions of a solvated electron with protic species) (57,58,61-65). The nonlinear interaction of ultrashort UV pulses (typically less than 100 fs in duration and having a power of 10 W cm" ) with water molecules triggers multiple electron photodetachment channels within a hydrogen bond network (see equations 4-7). An initial energy deposition via a two-photon absorption process (2 X 4 eV) leads to the formation of nonequilibrium states of an excess electron... 

The next paragraphs focus on the most recent advances in electron photodetachment processes in aqueous ionic solutions. Interesting results on ultrafast UV-IR spectroscopy of photoexcited aqueous chloride ions are presented in Figure 5-8. A complex photokinetic model of time-resolved data has been considered and explained in detail in recent pubhcations (85, 86). The primary photophysical and photochemical events triggered by one- or two-photon processes can be summarized with the following equations ... 

The HSCC equations have been solved for various Coulomb three-body processes, such as photoionization and photodetachment of two-electron systems and positronium negative ions [51, 105-111], electron or positron collisions [52, 112-115], ion-atom collisions [116-119], and muon-involving collision systems [103, 114, 120-125]. Figures 4.6, 4.7, 4.8, 4.9, and 4.10 are all due to HSCC calculations. Figure 4.12 illustrates the good agreement between the results of HSCC calculations [51] and the high-resolution photoionization experiment on helium [126]. See Ref. [127] for further detailed account of the comparison between the theory and experiment on QBSs of helium up to the threshold of He+(n = 9). 

Accurate measurements of the electron affinity of simple Ge and Sn radicals have been obtained by threshold photodetachment experiments carried out in ion cyclotron resonance experiments183. In these experiments, measurement of the threshold frequency for removing the electron from the anion yields an upper limit for the electron affinity of the species, as shown for GeH3- in equation 28. 

The time-resolved spectroscopy using 310 nm pulses of 100 fs duration has demonstrated that the electron solvation subsequent to a photodetachment of an electron proceeds through one intermediate state. At 1230 nm an intermediate state of electron appears with a time constant of 100 +/- 20 fs and relaxes towards a fully solvated species following a first order kinetics with a time constant of 220 +/- 30 fs. The signal observed in the red spectral region (720 nm) follows the kinetics defined by the equation of (figure ). 

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