Theory of Recombination

Some relatively new analyses in the theory of nonradiative transitions have followed from the fact that there is no basic reason why our three primary processes cannot also take place in combination. Thus Gibb et al. (1977) propose a process of cascade capture into an excited electronic state and subsequent multiphonon emission from there. The results of this model were applied to capture and emission properties of the 0.75-eV trap in GaP. A more detailed analysis has since been given by Rees et al. (1980). Similarly, cascade capture followed by an Auger process with a free carrier seems a quite likely process. However, we are not aware that such a model has as yet been suggested. The third possible combination of processes, namely Auger with multiphonon, has been examined by Rebsch (1979) and by Chernysh 

The Auger effect at a center can take place in various ways, since the three particles required for the process can be located on the particular center, on another center, and/or in the bands. The case of all three particles located at the center has been well treated fairly recently by Robbins and Dean (1978) and will therefore not be considered further. The remaining cases are those where either one or two particles are free (in one of the bands). For both these situations, the transition probability p depends on the free-carrier concentration it is customarily defined in terms of Auger coefficients and C, respectively, for one and two free carriers. For the case of one free hole, 

The Auger effect involving one free carrier, by definition, must include two trapped carriers. These two trapped carriers can be either on the same defect or on nearby defects. A further subdivision is that the two trapped carriers can 

Regarding centers that trap two electrons, these have been analyzed by Neumark (1973) on the basis of He type wave functions and, more recently, by Jaros (1978) and by Riddoch and Jaros (1980). One conclusion from this work is that quantitative values of Auger cross sections depend strongly on the band structure, with the transition matrix element (MA) given by Neumark (1973) as 

This process (Fig. 13) was first suggested by Lax (1959) as an explanation for large capture cross sections at some centers, the so-called giant traps. It has been adequately covered in previous reviews such as Landsberg (1970), Milnes (1973), Stoneham (1975), and Abakumov et al. (1978). The latter paper also includes a revised analysis of the process. Of more recent work, one should mention that of Beleznay and Andor (1978) they have carried out Monte Carlo calculations of this process and obtain improved agreement with observed cross sections (for GaAs as well as for Ge). Also, Pickin (1978,1979, 

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The theory of recombination for hydrogen and helium seems to be well understood, at least to 1 or 2 per cent, and the line intensities are not very sensitive to temperature or density in particular, there is no exponential factor. 

Ionization of atoms or molecules is the main primary event induced by the interaction of radiations with condensed matter. The charged species produced by ionization, if not removed from the irradiated system, will naturally tend to recombine. The conventional theories of recombination treat the transport and reactions of charged species only after the electrons ejected from atoms or molecules become thermalized by dissipating their initially high kinetic energies to the surrounding medium and form a spatial distribution around their parent cations. The thermalization in condensed phases is fast and is usually... 

Other novel work of Snider includes a paper36 on the kinetic theory of recombination and decay, which covers the whole range of concentrations from pure monomers to pure dimers. Thus it becomes possible to describe, in a uniform and consistent manner, the dynamical properties of a reacting gas of monomers and dimers. As well, the 1974 paper36 led to an understanding of the differences in predicted kinetic behavior if a dimer is treated as a pair of monomers. 

It is also interesting to make a comparison between the adiabatic theory and Eyring s theory of recombination reactions. If A and B are atoms, the "activated complex (AB) is considered /3/ as a rigid rotator whose partition function is... 

Piiiing M J and Smith i W M (eds) 1987 Modern Gas Kinetics. Theory, Experiment and Application (Qxford Biackweii) Giibert R G and Smith S C (eds) 1990 Theory of Unimolecular and Recombination Reactions (Qxford Biackweii) Fioibrook K A, Piiiing M J and Robertson S Fi (eds) 1996 Unimolecular Reactions 2nd edn (Chichester Wiiey)... 

Gilbert R G and Smith S C 1990 Theory of Unimolecular and Recombination Reactions (Oxford Blackwell)... 

Keck J 1960 Variational theory of chemical reaction rates applied to three-body recombinations J. Chem. Phys. 32 1035 Anderson J B 1973 Statistical theories of chemical reactions. Distributions in the transition region J. Chem. Phys. 58 4684... 

Flase W L 1976 Modern Theoretical Chemistry, Dynamics of Molecular Collisions part B, ed W H Miller (New York Plenum) p 121 Gilbert R G and Smith S C 1990 Theory of Unimolecular and Recombination Reactions koadoa Blackwell Scientific)... 

The theory of charge recombination in organic LEDs has been elaborated recently [110-113]. 

Historically, electrocatalytic science developed from investigations into cathodic hydrogen evolution, a reaction that can be reahzed at many metals. It was found in a number of studies toward the end of the nineteenth century that at a given potential, the rate of this reaction differs by severaf orders of magnitude between metals. In one of the first theories of hydrogen evofution, the recombination theory of hydrogen overvoltage, the rate of this reaction was finked directfy to the rate of the catalytic... 

It has been proven by experiment that there are donor acceptor atoms and molecules of absorbate and their classification as belonging to one or another type is controlled not only by their chemical nature but by the nature of adsorbent as well (see, for instance [18, 21, 203-205]). From the standpoint of the electron theory of chemisorption it became possible to explain the effect of electron adsorption [206] as well as phenomenon of luminescence of radical recombination during chemisorption [207]. The experimental proof was given to the capability of changing of one form of chemisorption into another during change in the value of the Fermi level in adsorbent [208]. 

Antireductionists wedded to alternative, non-erotetic accounts of explanation, cannot adopt the gambit of a Protagorian theory of explanation in any case. They will need a different argument for the claim that neither (G) nor (PS) can be explained by its macromolecular supervenience base, and for the claim that (PS) does explain (G), and (G) does explain individual cases of recombination. One argument such antireductionists might offer for the... 

An early theory of ionic recombination in liquids was developed by Jaffe (1913) for application at a relatively high LET. However, in Jaffe s theory, coulombic interactions are ignored and the positive and negative ions are assigned the same mobilities and distribution functions. Therefore, its use in a... 

Miller, W. H. Quantum mechanical theory of collisional recombination rates, J.Phys. Chem., 99 (1995), 12387-12390... 

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