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Leonid Rubinovich

Publications and source records attributed to Leonid Rubinovich.

4 recordsLinked to original sources
arXiv2026

Intrinsic Matching Frustration in Fluctuating Finite Systems

We formulate intrinsic matching frustration (IMF), a fluctuation-induced, kinetics-independent reduction in the mean capacity permitted by a prescribed matching rule. For complementary one-to-one matching, the instantaneous capacity is set by the minority population, so fluctuations produce a nonzero mean deficit even when the two populations are balanced on average. At finite size, this deficit depends on the full distribution of the population difference and is determined by its variance alone only in the Gaussian limit. Compartmentalization hides matching capacity by preventing cancellation between local imbalances of opposite sign. Fusion releases this hidden capacity monotonically under coarse graining, producing a measurable recovery of product yield following local reaction to completion.

physics.chem-ph↗
arXiv2020

Chemical Reactions under Nanoconfinement: Unravelling Equilibrium Constant Equations

Equilibrium Constant Differential Equations (ECDE) are derived for several nanoconfined elemental bimolecular reactions in the frameworks of statistical mechanics and the ideal gas model. The ECDEs complement the well-known equilibrium-constant ordinary equations that are used for macroscopic systems. Solving the ECDE numerically or analytically furnishes the average reaction extent, as well as its variance and skewness. This original theoretical-computational methodology fills the gap in studies of nanochemical equilibrium providing a consistent and convenient alternative to derivations based on direct employment of the canonical partition-functions. Whereas the latter become more complex and time-consuming with increased number of molecules, the ECDE-based computations are equally efficient for small as well as large numbers of nanoconfined reacting molecules. The ECDE methodology introduced here is confirmed by a complete agreement with partition-function computations. In addition, the new approach is applied to nanoconfined adsorption.

physics.chem-ph↗
arXiv2020

Modeling nanoconfined reaction kinetics: Alternative methodology incorporating equilibrium extent fluctuations

This study reveals that Equilibrium Constant Differential Equations (ECDE) for nanoconfined reactions derived recently in the frameworks of statistical mechanics are useful in modeling stochastic chemical kinetics. It is assumed and verified that if the transient value of the nano-reaction quotient is treated as being an equilibrium constant, the corresponding equilibrium reaction extent and its fluctuations (the variance function) coincide with the respective transient values. The ECDE-computed variance function facilitates the solution of the stochastic kinetics equations (SKE), as is demonstrated for a stoichiometric exchange reaction. The results obtained by this original methodology are in full agreement with those provided by the chemical master equations. Contrary to the commonly used approaches based on the latter and the Gillespie algorithm, which need a lot of computer memory and are time-consuming, the proposed SKE-ECDE method requires to solve only the ECDE and a single stochastic kinetics differential equation.

physics.chem-ph↗