Appendix D

A SIT fitting code, NONLINT-SIT (Personal communication, September 2004. A. R. Felmy, Pacific Northwest National Laboratory, Richland, WA, USA), was used in some systems to optimise ??fGm?? / RT values of different solid and aqueous species and SIT ion-interaction parameters, using solubility, ion-exchange, and solvent extraction data. From these, the optimised values of the different quantities can be compared with the other reported values. The program NONLINT-SIT is an extended version of the parameter optimisation programs (NONLIN and NONLINT) developed by A. R. Felmy using the MINPACK nonlinear least-squares programs, in conjunction with a Gibbs energy minimisation program (GMIN, [1990FEL] and [1995FEL]). The mathematical development of the latter is based on the formulations described in [1981HAR], [1987HAR/GRE] and [1985GRE/WEA]. GMIN and NONLIN have also been the bases for the development of the related parameter optimisation code INSIGHT, [1997STE/FEL], which uses the same algorithms as NONLINT, but deals with fewer types of experimental data.

Chemical Thermodynamics of Thorium, Volume 11

Appendix D

The Gibbs energy minimisation and optimisation program, NONLINT-SIT