Science, serendipity, coincidence, and the Oregonator at the University of Oregon, 1969-1974.

This historical review of the development of the Oregonator model of the Belousov-Zhabotinsky reaction is based on a lecture Dick Field presented during IrvFest2015-Celebrating a founding father of chaos!, a meeting in commemoration of Irving R. Epstein's 70 th birthday. For Dick's 80 th birthday festschrift, we focus here on the five papers in the series named "Oscillations in chemical systems," published in 1972 [Noyes et al.

Concentration fluctuations in fluid mixtures. II.

The method developed in a previous paper [R. Mazo, J. Chem.

Concentration fluctuations in fluid mixtures.

The B matrix of the Kirkwood-Buff theory of solutions describes number fluctuations of the component species. We show how, when the eigenvalues of the B matrix are widely different in magnitude, the description of the fluctuations can be simplified by restriction to a lower dimensional subspace of composition space. This simplification entails a loss of accuracy, which is argued to be often acceptable.

Chemical potentials in a three-component, 1-dimensional liquid.

The chemical potential of a dilute solute in a mixed solvent in a one-dimensional, three-component fluid model is calculated exactly. The results depend on three parameters derived from the interparticle potentials. An explicit formula for the leading deviations from ideality is obtained.

On the theory of solute solubility in mixed solvents.

A series of equations are developed for the study of the effects of cosolvents on the solubility of a solute in mixed solutions where the solute displays a finite solubility. The equations differ depending on the scale used for the solute (and cosolvent) concentrations. The expressions use Kirkwood-Buff integrals to relate the changes in solubility to changes in the local solution composition around the solute and can be applied to study any type of ternary system including electrolyte cosolvents.

Salting out near the critical point.

The salting out of solid solutes near the critical point of the solvent is investigated using the results of a previous paper (J. Phys. Chem.

A fluctuation theory analysis of the salting-out effect.

An analysis of the salting-out, or Sechenow, effect is given in terms of Kirkwood-Buff, or fluctuation, integrals. The analysis is formally exact but cannot easily be applied in its original form. When the solute that is being salted out is sparingly soluble, simplifications arise and the theory can be used to compute one of the Kirkwood-Buff integrals which is otherwise difficult to obtain.