Degradation spectrum

An early theory of the IT value was proffered by Spencer and Fano [44], based on the degradation spectrum. Another method, the Fowler equation, was employed by Inokuti [47] for electron irradiation, based on the approximation that there is only one ionization potential and that the ionization efficiency is unity. These restrictions can be relaxed. The main result of Inokuti s analysis may be given as follows. 

In order to estimate the contribution of secondary electrons, degradation spectrum, or in other words slowing down spectrum, is used. Degradation spectrum is defined as the length of the secondary electron trajectory, where the electron with the initial energy dissipates its energy between E and E+dE. 

Once we can obtain the degradation spectrum and the cross section of each reaction to produce the initial species, the yields of all the initial species are determined with the following equation [16] ... 

Figure 6 Contribution of the electron degradation spectrum to ionization and excitation in gaseous nitrogen calculated by binary-encounter collision theory with irradiation of 100-keV electron. (From Ref 15.)...

Recent years has seen a buigeoning interest in solid-phase organic synthesis protocols for the production of combinatorial libraries of new molecules [76,77]. A challenging factor in this approach is the analysis of the newly synthesised materials for which, ideally, direct structural analysis of the material would be carried out whilst still attached to the solid support and thus still available for further chemistry. The direct NMR analysis of such materials, even when solvated, is complicated by two principal factors which can severely degrade spectrum resolution ... 

The physical stage of a (3- or y-radiolysis of a sufficiently diluted medium is described in this theory (see Table I) as the interaction of the degradation spectrum of electrons with the ensemble of isolated molecules of the gas. The probabilities of individual inelastic collisions are characterized by their cross sections and the solution of the problem is,... 

No corresponding detailed theory of the action of slow electrons exists. Their fraction in the degradation spectrum is nevertheless so substantial that their contribution to the radiolysis must be considered as very important. The reason is that they are formed abundantly as secondary electrons from optical ionizations and contribute considerably... 

Figure 1. Subdivision of the degradation spectrum and contributions of its various regions to the total yield of primary activations...

In this relation, is the specific heat related to vibrational degrees of freedom of CO2 molecules the factor in parentheses is determined by the degradation spectrum Z(s) of 5-electrons in tracks (Nikerov Sholin, 1978, 1985) and nttmerically is about several electron volts (Belousov et al., 1979). The plasma effect in CO2 radiolysis is mostly related to stimulation of the reaction... 

As for the stopping power and the degradation spectrum, the W value is also a mean quantity and ionization fiuctuation is expected because of the various ways a deposited energy can be partitioned into ionizing and nonionizing events. The Fano factor represents such fluctuations, and it is defined as the ratio of mean square fluctuation of ionization to... 

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