Analytic representations of modified non-resonant thermonuclear reaction rates

Summary The basic physical principles common for the evaluation of all non-resonant thermonuclear reaction rates will be discussed. For the standard form of the nuclear reaction rate with Maxwell-Boltzmann distribution we give the closed-form representation by means of Meijer'sG-function. For physical reasons we consider the non-resonant thermonuclear reaction rate with modified Maxwell-Boltzmannian distribution and derive also its closed-form representation by means of Meijer'sG-function. Series representations for theG-functions appearing in non-resonant thermonuclear reaction rates are summarized and given in the Appendix, which can be used for the numerical computation of the reaction rate.

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Zusammenfassung Die grundlegenden physikalischen Prinzipien, die für die Berechnung von nichtresonanten thermonuklearen Reaktionsraten gelten, werden diskutiert. Wir geben für die Standardform der Kernreaktionsrate mit Maxwell-Boltzmannscher Verteilungsfunktion die geschlossene analytische Darstellung mit Hilfe der MeijerschenG-Funktion an. Aus physikalischen Gründen diskutieren wir die nichtresonante thermonukleare Reaktionsrate mit modifizierter Maxwell-Boltzmannscher Verteilungsfunktion und geben auch hier die geschlossene Darstellung mittels der MeijerschenG-Funktion. Für die für nichtresonante Kernreaktionsraten charakteristischeG-Funktion werden Reihendarstellungen vorgeschlagen, die für die numerische Auswertung von Kernreaktionsraten nützlich sind.

     

On generalized distributions and pathways

The scalar version of the pathway model of Mathai [A.M. Mathai, Linear Alg. Appl. 396 (2005) 317] is shown to be associated with a large number of probability models used in physics. Different families of densities are listed here, which are all connected through the pathway parameter α, generating a distributional pathway. The idea is to switch from one functional form to another through this parameter and it is shown that one can proceed from the generalized type-1 beta family to generalized type-2 beta family to generalized gamma family. It is also shown that the pathway model is available by maximizing a generalized measure of entropy, leading to an entropic pathway, covering the particularly interesting cases of Tsallis statistics [C. Tsallis, J. Stat. Phys. 52 (1988) 479] and superstatistics [C. Beck, E.G.D. Cohen, Physica A 322 (2003) 267].     

ChemInform Abstract: 3s-Gd2C2Br2, an Isomorph with a New Stacking Sequence

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