Electronic Resource
College Park, Md.
:
American Institute of Physics (AIP)
The Journal of Chemical Physics
94 (1991), S. 4495-4508
ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The process of thermalization of a hot subexcitation photoelectron in polar medium is studied. The master equation is used as a starting point to derive analytic expression for the thermalization distances distribution function. The resulting expression depends upon the mechanism of energy dissipation via the first two moments of the energy loss probability. Asymptotic decay of the distribution with the distance depends on the character of electron motion (exponential for the ballistic motion; Gaussian for the diffusion). A general scheme was developed for evaluation of the energy loss probability within the framework of the linear response theory. Explicit results are derived for electron thermalization in polar medium whose dissipative properties are characterized by the Debye macroscopic dielectric susceptibility function (the Fröhlich–Platzman model). Comparison of the estimates of thermalization distance in water with the experiment shows that the randomization of the direction of the electron motion is much faster than the thermalization process. The dependence of the most probable (average) thermalization distance on the initial kinetic energy, En, and on the dielectric relaxation time, τD, is found for the ballistic and the diffusive motion of the electron (∝E3/4nτ 1/2D for diffusive motion). An explicit relation is derived between the probability to escape geminate recombination and the excess kinetic energy as well as the polarity of the medium and its relaxation time. Results are used to interpret the recent experimental data on the yield and kinetics of geminate recombination in normal and heavy water.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.460605
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