Resonant reactions

When the compound nucleus has an excited level coinciding in energy with that of the projectile in the CM system, i.e. the projectile energy E is close to Ep where 

A narrow resonance not too far from the Gamow peak may supplant the latter (see Fig. 2.11). The reaction rate coefficient is then given in analogy to Eq. (2.53) by 

The dependence of T on energy for charged-particle decay can be found as follows. The decay rate is the probability density flux integrated over surface area at infinity, i.e. 

When there are only two possible decay channels for the excited state of the compound nucleus, i.e. T = Va + Vh, two simple limiting cases arise  

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This method, introduced originally in an analysis of nuclear resonance reactions, has been extensively developed [H, 16 and F7] over the past 20 years as a powerful ab initio calculational tool. It partitions configuration space into two regions by a sphere of radius r = a, where r is the scattered electron coordinate. 

Ion beam profiling techniques have been used to determine the total content and concentration versus depth of hydrogen in a-Si H (Lanford et al., 1976 Brodsky et al., 1977b Ziegler et al., 1978 Milleville et al., 1979). An a-Si H sample is bombarded with 15N ions, which can undergo a resonant reaction. 

For non-resonant reactions, the. S -factor defined in Eq. (2.22) is a slowly varying quantity which can be replaced by an appropriate mean value, i.e. 

Alternative resonance reactions with emitted photons resonant with absorption on the constituents of explosives include the following ... 

Obsidian is a volcanic glass frequently used as tool by prehistoric men. The thickness of the hydration layer that has developed on the surface of the artifact since it was made can be used to date it. Measurement of the hydration layer is carried out by a variety of instrumental techniques. Among them are nuclear resonance reactions, LM, PAS, XPS, XANES, sputter-induced optical spectrometry (SIPS), and SIMS [70]. 

The dynamics of a reaction that proceeds directly over the transition state is expected to be qualitatively different from that of a resonance-mediated reaction. In particular, one expects that the branching ratios into the product rovibrational states will be very different between the direct and the resonant mechanisms. For example, if a given Feshbach resonance corresponds to trapping on the v = 1 vibrationally adiabatic curve, then one might expect that the population of the v = l vibrational state of the product molecule may be greatly enhanced by the resonant mechanism. Similarly, the rotational product distribution resulting from the fragmentation of a resonance molecule may show a quite distinct pattern from that of a direct reaction. Indeed, Liu and coworkers [94], and Nesbitt and coworkers [95] have noted distinct rotational patterns in the F+HD resonant reaction. 

Wigner, E.P. and Eisenbud, L. (1947). Fligher angular momenta and long range interaction in resonance reactions, Phys. Rev. 72, 29 11. 

D. Grambole, C. Bauer, P. Gippner, C. Heiser, W. Rudolph, H.J. Thomas, Fluorine determination in the near surface region of solids using the 19F(p,p y)19F resonance reaction, J. Radioanal. Nucl. Chem. Articles 83 (1984) 107-115. 

The design of the reaction section offers several alternatives. Plug-flow-like reactor type gives the best productivity with resonable reaction times from 10 to... 

In aurora the Meinel radiation is probably affected by the near-resonant reaction [209, 210] ... 

Similarly, the cross sections for the near-resonant reactions,... 

As the resonance reaction constant (resonance demand parameter) in equation (2a) for nucleophilic reactions is symbolized as r, the resonance demand parameter in equation (2) should be symbolized as r. However, we are dealing with only electrophilic reactions and equilibria, so that the resonance demand parameter is simply represented as r in equation (2) deleting superscript... 

Substitution of the particular fluorine shown is favored because the intermediate anion formed is stabilized by delocalization of the charge on the keto oxygen (resonance). Reaction at the carbon bearing the other fluorine would result in an intermediate in which the negative charge could not be delocalized onto this oxygen. 

In the first case one may measure the weight gain of a specimen during oxidation. Unfortunately, this is a very time-consuming method (months to years). Another possibility is the analysis of the oxide by means of the methods mentioned in Sect.4.2 a-backscattering, nuclear resonance reactions. Auger spectroscopy and ESC A in particular have been used (Chap. 6.1). 

The electron-impact ionization does not occur in the cascade arc torch, and the energy transfer between excited neutrals of the carrier gas and the added gases becomes a dominant reaction, i.e., the Penning-type reactions or resonance reactions between gas molecules and excited neutrals of the carrier gas is the principal generation process for the reactive species. ... 

The question of how fine-tuned this level needs to be for the existence of carbon-based life has been the subject of considerable research. Tire most recent work on this topic was done by Oberhummer and collaborators (see, for example, Ober-hummer et al., 2000 Csoto et al., 2001 Schlattl et al., 2004). These authors used a model that treats the nucleus as a system of 12 interacting nucleons, with the approximate resonant reaction rate... 

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