Most probable event

When averaged over the distribution of energy loss for a low-LET radiation (e.g., a 1-MeV electron), the most probable event in liquid water radiolysis generates one ionization, two ionizations, or one ionization and excitation, whereas in water vapor it would generate either one ionization or an excitation. In liquid water, the most probable outcomes for most probable spur energy (22 eV) are one ionization and either zero (6%) or one excitation (94%) for the mean energy loss (38 eV), the most probable outcomes are two ionizations and one excitation (78%), or one ionization and three excitations (19%). Thus, it is clear that a typical spur in water radiolysis contains only a few ionizations and/or excitations. 

The most common method of ionisation involves Electron Impact (El) and there are two general courses of events following a collision of a molecule M with an electron e. By far the most probable event involves electron ejection which yields an odd-electron positively charged cation radical [M]+ of the same mass as the initial molecule M. 

For evaluating the extent of regulatory action based on exposure and social mobilisation, this thesis has devised a set of most-probable events that can be evaluated in terms of their potential for being of general regulatory concern, which form indicators for extent of regulatory action based on exposure or extent of regulatory action based on social mobilisation . As a separate step, it is proposed that those events be evaluated in terms of the probability of exposure... 

In so doing, we obtain the condition of maximum probability (or, more properly, minimum probable prediction error) for the entire distribution of events, that is, the most probable distribution. The minimization condition [condition (3-4)] requires that the sum of squares of the differences between p and all of the values xi be simultaneously as small as possible. We cannot change the xi, which are experimental measurements, so the problem becomes one of selecting the value of p that best satisfies condition (3-4). It is reasonable to suppose that p, subject to the minimization condition, will be the arithmetic mean, x = )/ > provided that... 

Theoretical models presented in previous sections give no information on distributions of mass, velocity, or range of fragments, and very little information on the number of fragments to be expected. Apparently, these models are not developed sufficiently to account for these parameters. More information can probably be found in the analysis of results of accidental explosions. It appears, however, that vital information is lacking for most such events. 

Even more remarkable, vibrational relaxation of NO(r = 15) on Au(lll) is characterized by profound multi-quantum vibrational relaxation. Specifically, the most probable vibrational scattering channel releases more than 150kJmol-1. Vibrational relaxation events exchanging as many as 10 vibrational quanta are observed. It appears likely that even more vibrational quanta can be exchanged with significant efficiency, but background problems prevented the observation of these channels. Thus the reported... 

Abstract Gamma-ray bursts are the most luminous and probably the most relativistic events in the universe. The last few years have seen a tremendous increase in our knowledge of these events, but the source of the bursts still remains elusive. I will summarize recent progress in this field with special emphasis on our understanding of the possible progenitor systems. 

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