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We present in this work a very short proof for the existence, uniqueness and smoothness in dimensions $d\leq 3$ of the system of reaction diffusion $ \partial\_t a\_i - d\_i \Delta a\_i = (-1)^i (a\_1 a\_3 - a\_2 a\_4)$, where $a\_i \geq 0$…

Analysis of PDEs · Mathematics 2026-05-25 Hector Bouton , Laurent Desvillettes , Helge Dietert

We present a unified formalism for describing chemical reaction rates of trapped, ultracold molecules. This formalism reduces the scattering to its essential features, namely, a propagation of the reactant molecules through a gauntlet of…

Quantum Physics · Physics 2015-05-19 Zbigniew Idziaszek , Goulven Quéméner , John L. Bohn , Paul S. Julienne

We consider the coagulation dynamics A+A -> A and the annihilation dynamics A+A -> 0 for particles moving subdiffusively in one dimension, both on a lattice and in a continuum. The analysis combines the "anomalous kinetics" and "anomalous…

Statistical Mechanics · Physics 2007-05-23 S. B. Yuste , Katja Lindenberg

Morphogenesis is central to biology but remains largely unexplored in chemistry. Reaction-diffusion (RD) mechanisms are, however, essential to understand how shape emerges in the living world. While numerical methods confirm the incredible…

Pattern Formation and Solitons · Physics 2014-07-17 Anton S. Zadorin , Yannick Rondelez , Jean-Christophe Galas , André Estevez-Torres

Most biochemical reactions in living cells rely on diffusive search for target molecules or regions in a heterogeneous overcrowded cytoplasmic medium. Rapid re-arrangements of the medium constantly change the effective diffusivity felt…

Statistical Mechanics · Physics 2019-11-13 Yann Lanoiselée , Nicolas Moutal , Denis S. Grebenkov

Accurate nuclear reaction rates are needed for primordial nucleosynthesis and hydrostatic burning in stars. The relevant reactions are extremely difficult to measure directly in the laboratory at the small astrophysical energies. In recent…

Nuclear Theory · Physics 2009-01-22 C. A. Bertulani

In a reaction-diffusion system, fluctuations in both diffusion and reaction events, have important effects on the steady-state statistics of the system. Here, we argue through extensive lattice simulations, mean-field type arguments, and…

Soft Condensed Matter · Physics 2013-06-12 Fernando Peruani , Chiu Fan Lee

Autocatalytic reaction between reacted and unreacted species may propagate as solitary waves, namely at a constant front velocity and with a stationary concentration profile, resulting from a balance between molecular diffusion and chemical…

Fluid Dynamics · Physics 2009-11-07 M. Leconte , J. Martin , N. Rakotomalala , D. Salin

We briefly review some aspects of the anomalous diffusion, and its relevance in reactive systems. In particular we consider {\it strong anomalous} diffusion characterized by the moment behaviour $\langle x(t)^q \rangle \sim t^{q \nu(q)}$,…

Statistical Mechanics · Physics 2016-09-06 Fabio Cecconi , Davide Vergni , Angelo Vulpiani

We study irreversible A-B reaction kinetics at a fixed interface separating two immiscible bulk phases, A and B. We consider general dynamical exponent $z$, where $x_t\sim t^{1/z}$ is the rms diffusion distance after time $t$. At short…

Soft Condensed Matter · Physics 2007-05-23 Ben O'Shaughnessy , Dimitrios Vavylonis

Radiative association and photodissociation rates are calculated for quadrupole transitions of H2. A complete set of bound and unbound states are included in a self-consistent master equation to obtain steady-state concentrations for a…

Astrophysics of Galaxies · Physics 2016-10-12 Robert C. Forrey

The temperature dependence of the rate of the reaction CH_4+H \to CH_3+H_2 is studied using classical collision theory with a temperature-dependent effective potential derived from a path integral analysis. Analytical expressions are…

Chemical Physics · Physics 2016-09-08 David Z. Goodson , Dustin W. Roelse , Wan-Ting Chiang , Steven M. Valone , J. D. Doll

Metallic nanoparticles embedded in stimuli-responsive polymers can be regarded as nanoreactors since their catalytic activity can be changed within wide limits: the physicochemical properties of the polymer network can be tuned and switched…

Chemical Physics · Physics 2015-07-22 Stefano Angioletti-Uberti , Yan Lu , Matthias Ballauff , Joachim Dzubiella

Context. Monte Carlo methods have enabled nuclear reaction rates from uncertain inputs to be presented in a statistically meaningful manner. However, these uncertainties are currently computed assuming no correlations between the physical…

Instrumentation and Methods for Astrophysics · Physics 2017-08-02 Richard Longland

The direct measurement of the reaction or capture (fusion) cross section is a difficult task since it would require the measurement of individual cross sections of many reaction channels, and most of them could be reached only by specific…

Nuclear Theory · Physics 2015-06-18 V. V. Sargsyan , G. G. Adamian , N. V. Antonenko , P. R. S. Gomes

Catalyst particles or complexes suspended in liquid films can trigger chemical reactions leading to inhomogeneous concentrations of reactants and products in the film. We demonstrate that the sensitivity of the liquid film's gas-liquid…

Soft Condensed Matter · Physics 2024-02-23 Tilman Richter , Paolo Malgaretti , Thomas M. Koller , Jens Harting

We consider a reaction-diffusion system which may serve as a model for a ferment catalytic reaction in chemistry. The model consists of a system of reaction diffusion equations with unbounded time dependent coefficients and different…

Analysis of PDEs · Mathematics 2022-06-14 Mohamed Majdoub , Nasser-eddine Tatar

Elastic scattering observables (differential cross section and analyzing power) are calculated for the reaction $^6$He(p,p)$^6$He at projectile energies starting at 71 MeV/nucleon. The optical potential needed to describe the reaction is…

Nuclear Theory · Physics 2013-05-30 S. P. Weppner , Ch. Elster

Catalysis, the acceleration of product formation by a substance that is left unchanged, typically results from multiple elementary processes, including diffusion of the reactants toward the catalyst, chemical steps, and release of the…

Chemical Physics · Physics 2023-12-27 Yann Sakref , Maitane Muñoz-Basagoiti , Zorana Zeravcic , Olivier Rivoire

The empirical velocity of a reaction-diffusion front, propagating into an unstable state, fluctuates because of the shot noises of the reactions and diffusion. Under certain conditions these fluctuations can be described as a diffusion…

Statistical Mechanics · Physics 2020-08-26 Evgeniy Khain , Baruch Meerson , Pavel Sasorov