Recoil Mixing

In addition to recoil mixing, other ballistic phenomena are possible during ion irradiation and implantation. For example, enhanced atomic mixing can occur when multiple displacements of target atoms result from a single incident ion. In the multiple displacement process, an initially displaced target atom (primary recoil) continues the knock-on-atom processes, producing secondary recoil atom displacements which in turn displace additional atoms. The multiple displacement sequence of collision events is commonly referred to as a collision cascade. 

This momentum space potential is similar to the momentum space potential corresponding to insertion of the electron-loop polarization in the Coulomb photon, considered in Subsubsect. 7.1.1.1. The only difference is in the overall multiplicative constant, and that the respective expression in the case of the one electron polarization insertion contains in the denominator instead of k in (7.46). This means that the mixed loop contribution is suppressed in comparison with the purely electron loops by an additional recoil factor... 

The error bars of this last estimate are still rather large, and more accurate calculation would be necessary in pursuit of all corrections of the scale of 10 Hz. The relatively large magnitude of the mixed logarithm contribution in (10.11) warrants calculation of the contribution which is linear in the logarithm of the mass ratio and nonlogarithmic in Za. All recoil corrections are collected in Table 10.1. The uncertainty of the total recoil correction in the last line of this Table includes an estimate of the magnitude of the yet unknown recoil contributions. 

Whereas several transient species have been observed for dioxygen activation by MMOH, no intermediates were found by rapid-mixing spectroscopic methods for the actual methane hydroxylation step. Mechanistic probes, i.e. certain non-natural substrates that are transformed into rearranged products only if the reaction proceeds via a specific intermediate such as a radical or a cation, give ambivalent results Some studies show that products according to a pathway via cationic intermediates are obtained in sMMO hydroxylations and at least one study suggests the presence of a radical intermediate [40]. Computational analyses of the reaction of MMOHq with methane suggest a so-called radical recoil/rebound mechanism in which MMOHq... 

There are some special methods of chemical synthesis recoiling phenomenon (recoil synthesis). For example anthracene labelled with " C is synthesised by irradiating acridine with neutrons through N(n,p) C reaction. Similarly labelling is realised with the use of He( ,p) H or Li(n,a) H. For this purpose the compound to be labelled is mixed with He gas or Li,COj and then irradiated with neutrons. 

The theory that the oxygenated recoil species are formed in reactions between recoil atoms and surrounding oxyanions or dislodged oxygens is supported by the results of mixed crystal experiments. Mixed crystals (solid solutions) of potassium chromate in potassium sulfate [35) and fluoberyllate (50), and potassium permanganate in potassium perchlorate (67) have been investigated. The results are given in Table II. These... 

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