Oscillator strength electron energy distribution

Here/(q) is the dipole oscillator strength distribution at q and e is the base of natural logarithm. The lowest excitation potential may be taken for qmin, whereas qmax = (E + EB)/2 with EB a defined mean electron binding energy (Mozumder and La Verne, 1984). 

Oddershede s earlier results [3-5] calculate the directional values of the dipole oscillator strength distribution for use in the Bethe theory [9], which is valid for high-energy projectiles. Our approach, since we have not implemented the possibility of treating unbound electrons, is restricted to calculating stopping cross... 

Figure 4 Relative dipole oscillator strength distribution,/( ), for liquid water [63] and frequency of a given energy loss by 1-MeV electrons in liquid water [64].

A detailed PPP-CI investigation of the unsubstituted pyrylium and thiopyrylium cations has been carried out by Japanese authors (72T5873). Electronic transition energies, oscillator strengths, 7r-orbital energies, tt-electronic distributions, and 7r-bond orders were reported. From the amount of decrease of the positive charge on the heteroatom, the contribution of carbocationic resonance hybrid structures has been found to be 14.6% for thiopyrylium and 28.4% for pyrylium. 

In practice one either measures the angular distribution of the scattered electrons and plots f(K) as a function of K, and extrapolates the resulting curve to K = 0 and fits this curve to the known optical oscillator strength /(O), or one carries out the experiment at high impact energy and low (preferably zero) scattering angle and assumes that the optical limit has been achieved. 

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