Problems In Physical Chemistry Research Articles

Erratum: Solution of Kramers–Moyal equations for problems in chemical physics [J. Chem. Phys. 81, 1285 (1984)

Erratum: Solution of Kramers–Moyal equations for problems in chemical physics [J. Chem. Phys. <b>81</b>, 1285 (1984)

Solution of Kramers–Moyal equations for problems in chemical physics

We derive asymptotic solutions of Kramers–Moyal equations (KMEs) that arise from master equations (MEs) for stochastic processes. We consider both one step processes, in which the system jumps from x to x+ε or x−ε with given probabilities, and general transitions, in which the system moves from x to x+εξ, where ξ is a random variable with a given probability distribution. Our method exploits the smallness of a parameter ε, typically the ratio of the jump size to the system size. We employ the full KME to derive asymptotic expansions for the stationary density of fluctuations, as well as for the mean lifetime of stable equilibria. Thus we treat fluctuations of arbitrary size, including large fluctuations. In addition we present a criterion for the validity of diffusion approximations to master equations. We show that diffusion theory can not always be used to study large deviations. When diffusion theory is valid our results reduce to those of diffusion theory. Examples from macroscopic chemical kinetics and the calculation of chemical reaction rates (‘‘Kramers’’ models) are discussed.

Symmetry operators of generalized wreath products and their applications to chemical physics

AbstractSymmetry operators of generalized wreath product groups are formulated. Several applications of these operators to nonrigid molecular problems in chemical physics are outlined.

Lamé's functions and ellipsoidal harmonics for use in chemical physics

A general method for computing the coefficients, at any order, of the Lamé's functions used to define a set of orthogonal polynomials called ellipsoi The use of such harmonics in chemical physics problems is illustrated by the calculation of the free energy of a molecule seperated from a dielectric c

Some problems of chemical physics of ageing and stabilization of polymers

Ageing of polymers was examined as a complex process taking place by a sole mechanism. The major role of free-radical reactions in this process was indicated. A study was made of the effect of molecular mobility of polymers on reaction kinetics in a polymer matrix. Results were examined of the three dimensional heterogeneity of reaction kinetics in polymers, which is related to structural heterogeneity (“kinetic interruption” of the reaction). Results were presented of a study of elementary reaction kinetics in polymers. A study was made of the relation between ageing kinetics and the variation of practically important properties of polymers. Mechanisms of stabilization of polymer materials were described and new principles of stabilization proposed. Data were given of an investigation into ageing kinetics of polymers under extremal conditions, by the action of UV light, in corrosive media and in tissues of living organism. Some problems of polymer combustion were discussed.

Solutions to certain classes of linearized reaction–diffusion equations

A systematic study is presented for the linear manifold of solutions to a generic system of reaction–diffusion equations in the neighborhood of a constant uniform (equilibrium) solution. The theory pertains directly to an arbitrary number of reacting and diffusing molecular or biological species in an arbitrary bounded spatial (1-, 2- or 3-dimensional) region with an impermeable boundary, so that the normal gradient of any species concentration function is zero at all boundary points. The stability analysis developed by previous authors is streamlined here for the case of two reacting and diffusing species, worked out completely for the case of three species, and made more amenable to specialized treatment for cases with four or more species. With the use of modern algebraic computational methods, explicit analytical general solutions to the linearized reaction–diffusion equations are derived for certain classes of model theories. These results either apply directly or admit extension to a wide range of practical reaction–diffusion problems in physical chemistry and biology.

Principles and Problems in Physical Chemistry for Biochemists.Nicholas C. Price , Raymond A. Dwek

<i>Principles and Problems in Physical Chemistry for Biochemists.</i>Nicholas C. Price , Raymond A. Dwek

Problems in physical chemistry (Wood, A.)

Problems in physical chemistry (Wood, A.)

Principles and Problems in Physical Chemistry for Biochemists

Principles and Problems in Physical Chemistry for Biochemists

An application of symbolic computation to crystal physics

This paper describes a practical application of symbolic computation to a problem in chemical physics. We compute a series approximation to a fairly complicated integral using straightforward techniques, allowing the computer to take over when the problem becomes too messy. Even though Altran [1] has no direct way to handle non-rational functions, introducing a few auxiliary variables renders the problem tractable. We certainly hope that more users will attempt to solve standard problems of this sort using symbolic manipulation programs.

Gel Filtration of Starch–Iodine System

Abstract The well-known starch-iodine reaction was taken up to study the applicability of gel filtration to the problem of physical chemistry. Gel filtration by the frontal analysis was carried out, the following results being obtained. (1) Soluble starch- and amylose–iodine systems give elution volumes of iodine containing constituents (Vsi and Vai, respectively) distinctly smaller than that of iodine, which decrease with increasing concentration of iodine, C, and starch, approaching the elution volume of starch. This is a direct experimental evidence of starch–iodine complex formation. (2) An equation derived for Vsi vs. C and Vai vs. C relations holds satisfactorily. The concentration of free iodine in equilibrium with the complex is calculated by the equation. (3) Presence of iodide ion facilitates the complex formation, but its decomposition is instantaneous when it is isolated from free iodine. (4) Some iodide ions are found to be incorporated in the complex. (5) Amylopectin also forms a complex with iodine, but the amount of iodide incorporated is not large. (6) Potentiometric titration of starch with iodine exhibits a similar behavior to the gel filtration measurement.

Systems with internal parameters obeying the orthogonality condition

The thermodynamic orthogonality principle established by the author is applied to constitutive equations of viscoelastic materials and to a simple problem in Physical Chemistry.

Packing Density of Ternary Mixtures of Spheres

KNOWLEDGE of the mechanics of systems of large particles has lagged behind that of the other states of matter and probably all the results of any significance before 1958 have been compiled by Deresiewicz1. Here we describe some measurements of the packing densities of ternary mixtures of spheres. This is relevant to industries which have to handle granular materials and to problems in chemical physics associated with the study of volumes of mixtures of liquids composed of spherical atoms or molecules.

Book Review: Rechenseminar in physikalischer Chemie. (Problems in Physical Chemistry). By K. Torkar

Angewandte Chemie International Edition in EnglishVolume 9, Issue 11 p. 914-914 Book Review Book Review: Rechenseminar in physikalischer Chemie. (Problems in Physical Chemistry). By K. Torkar Gerd Wedler, Gerd WedlerSearch for more papers by this author Gerd Wedler, Gerd WedlerSearch for more papers by this author First published: November 1970 https://doi.org/10.1002/anie.197009142AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume9, Issue11November 1970Pages 914-914 RelatedInformation

Physical chemistry problems and solutions by L. C. Labowitz and J. S. Arents

<i>Physical chemistry problems and solutions</i> by L. C. Labowitz and J. S. Arents

Physical chemistry problems and solutions (Labowitz, Leonard C.; Arents, John S.)

Physical chemistry problems and solutions (Labowitz, Leonard C.; Arents, John S.)

Applied Physical Chemistry Problems: For Chemists and Chemical Engineers (Smith, A. C. K.)

Applied Physical Chemistry Problems: For Chemists and Chemical Engineers (Smith, A. C. K.)

Collection of Problems in Physical Chemistry

Collection of Problems in Physical Chemistry

Rigorous least squares adjustment: Application to some non-linear equations, I

The primary purpose of this paper is to apply the general theory of least squares adjustment to problems in physical chemistry.

Collection of Problems in Physical Chemistry.

<b>Collection of Problems in Physical Chemistry.</b>