The Chemical Kinetics Simulator (CKS) program is a scientific software tool developed by chemists at IBM's Almaden Research Center. It provides the bench scientist with an easy-to-use, rapid, interactive method for the accurate simulation of chemical reactions. CKS is completely self-contained, and requires no programming or extensive user training. This lets the user become immediately productive, even without a background in numerical analysis. Academic, government and industrial scientists and engineers in more than 75 countries are using CKS to solve problems and instruct students in chemistry and chemistry-related sciences ranging from cell biology to environmental science, food science to polymer synthesis, geology to materials science, reactor engineering to pharmacology. CKS is an ideal tool for teaching the principles of chemical reaction kinetics to students and trainees.

CKS does not integrate sets of coupled differential equations to predict the time history of a chemical system. Instead, it uses a general, rigorously accurate stochastic algorithm to propagate a reaction. The stochastic method for kinetics simulations was first published in the early 1970's by Professor D. L. Bunker (University of California at Irvine)(1), and by Dr. D. Gillespie(2), (Naval Weapons Center, China Lake). The stochastic method is comparable in efficiency to integration for simple kinetic schemes, and significantly faster for stiff systems. It is superior for modeling reactions which depend on sporadic events and fluctuations, such as explosions and nucleation, and handles easily complex situations such reactions in continuously changing volumes. A particularly useful feature of stochastic simulation methods is that they offer enhanced flexibility in setting up reaction mechanisms since they do not require explicit checking for conservation of mass and energy.

(1) D. L. Bunker, B. Garrett, T. Kliendienst and G.S. Long III, Combustion and Flame, Vol 23, p 373 (1974).
(2) D. T. Gillespie, Journal of Computational Physics, Vol 22, p 403 (1976).

Simulator Features

The simulator

• General-purpose, stand-alone stochastic chemical kinetics simulator
• Well suited for modeling both simple and complex chemical kinetics in gas, solution and solid phases
• Useful for chemical processes involving large dynamic ranges of variables, fluctuations and instabilities
• Requires no additional programming by the user
• Reaction mechanisms are entered using conventional chemical notation
• Single-valued or Arrhenius rate constants
• User-configurable time, energy and concentration units
• Independently selectable temperature, volume and pressure conditions
• Capability for isothermal, adiabatic, and programmed temperature reactions
• Pressure and volume can be held constant or allowed to vary
• Equilibrium detection and emulation function that can dramatically improve simulator performance
• No pre-defined limit on the number of reaction steps or species in a mechanism (except for limitations imposed by Microsoft Windows): simulations can run up to 4 billion data points
• CKS's simulation runs as a background process, leaving the user interface available for setting up new simulations or viewing results from a previous simulation. CKS can multitask with other applications such as word processors and graphics programs.

• Full on-line, context-sensitive help for every window
• Integrated notebook
• Capability to have up to nine reaction schemes loaded into memory at once
• Visual indicators to track progress of a simulation
• Simulations can be interrupted, inspected and resumed
• Up to eight simulations can be set up and placed in a queue for unattended runs
• Flexible graphical display of simulation results
• Direct overlay of experimental results on simulated data
• Hardcopy output in PostScript, HPGL and tabular form, or as direct printout to an attached printer
• Reaction scheme description printout

All other functions of version 1.01 of the simulator are the same as in version 1.0.

View a screen shot of CKS for OS/2 (23 KB file)

View a screen shot of CKS for Windows (23 KB file)

View a screen shot of CKS for Macintosh (17 KB file)

This screen shows the reaction scheme and plot windows from the polyimid.rxn demo, which simulates curing of polyimide under the control of a stepped temperature profile (profile shown in the temperature vs time plot). The significant volume shrinkage that occurs during curing is also plotted.

CKS comes with a manual and an extensive library of demonstration simulations that show you the kinds of systems that can be studied with it and that illustrate techniques for handling various types of physical situations. The library includes simulations of gas phase, solution phase and solid state reactions such as co- and terpolymerization ... radical chain-initiated polymerization (including a sample spreadsheet for extracting molecular weight distributions) ... kinetic resolution of enantiomeric mixtures ... chemistry in supercritical media ... pH-dependent model enzyme kinetics ... thermogravimetric analysis ... temperature programmed desorption ... smog chemistry ... silane chemistry in a chemical vapor deposition reactor ... model batch and flow catalytic reactors ... curing of polymers with significant volume shrinkage ... synthetic protocols for preparation of a photosensitizer ... and the Oregonator chemical oscillator.

About the authors