Capture model cross-section

Gray, S.K.. Goldfield, E.M.. Schatz, G.C. and Balint-Kurti, G.G. (1999) Helidty decoupled quantum dynamics and capture model cross sections and rate constants... 

Similar to the hard-sphere collision model, the capture colhsion cross section or the Langevin cross section is defined as ... 

These shell closures have a profound influence on nuclear properties, in particular the binding energy (adding terms not accounted for in Eq. 2.2), particle separation energies and neutron capture cross-sections. The shell model also forms a basis for predicting the properties of nuclear energy levels, especially the ground... 

Capture Model and Total Reactive Cross Sections... 

The study of artificial photosynthesis has been the subject of ongoing attention for many years now due to the need for sustainable energy resources. In natural photosynthesis a lightharvesting antenna system with a large optical cross-section (for example the LH2 complex) absorbs a photon that is funneled by energy transfer (ET) to the reaction centre [1-3]. Excellent candidates to mimic the natural antenna system are molecules that efficiently absorb light and are able to transfer the captured energy to other parts of the molecule. Molecules based on Zn and free-base porphyrins are examples of compounds that can be used as models for the LID complex [4]. 

In this equation, jjl is the reduced mass of the system, and o-inv is the cross section for the inverse process in which the particle b is captured by the nucleus B where b has an energy, Eb. The symbols p(E B) and p( c) refer to the level density in the nucleus B excited to an excitation energy E% and the level density in the compound nucleus C excited to an excitation energy, . The inverse cross section can be calculated using the same formulas used to calculate the compound nucleus formation cross section. Using the Fermi gas model, we can calculate the level densities of the excited nucleus as... 

The lifetime may be of the order of seconds (72,76). Subsequently, he obviated this difficulty by assuming a small capture cross section. His new model (215)... 

The shape resonances have been described by Feshbach in elastic scattering cross-section for the processes of neutron capture and nuclear fission [7] in the cloudy crystal ball model of nuclear reactions. These scattering theory is dealing with configuration interaction in multi-channel processes involving states with different spatial locations. Therefore these resonances can be called also Feshbach shape resonances. These resonances are a clear well established manifestation of the non locality of quantum mechanics and appear in many fields of physics and chemistry [8,192] such as the molecular association and dissociation processes. 

B4++ He reaction. This collisional system has been investigated theoretically within the framework of the semiclassical close-coupling formalism using different model potential approaches [2,3] which lead to a discrepancy of about a factor 5 for the double capture cross section values. We have thus performed an alternative study of this system by means of a full molecular expansion method, focusing our attention on the double electron capture process. 

Once concentrated in the center, neutralinos annihilate copiously. The annihilation rate is maximal when all captured neutralinos annihilate (a condition called equilibrium between capture and annihilation). Whether this condition is satisfied depends on the relative strength of the annihilation and scattering cross sections, and ultimately on the parameters of the particle and halo models. (See Jungman, Kamionkowski Griest (1996) and references therein for complete formulas.)... 

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