React3 is a Macintosh application for modeling and fitting chemical reaction mechanisms. It is a complete rewrite of React2 and is presented in compiled form for Macintosh computers. A sample input mechanism looks like: This mechanism is a test with an analytic solution 0.5 * A --> B 0.10 B + A --> C a silly test where the * indicates a least-squares adjustable rate, lines containing an arrow --> are reactions and all other lines are ignored. There is a MS WORD manual and a plaintext filter of the manual with examples and usage instructions. all is packed in a self extracting archive encoded in MacBinary II Consider this a test copy. Let me know how it works and what Mac and OS you are using if there is trouble. It was compiled under 7.5.1 using Think C/C++ 7.0 on my personal Performa 6115CD (601 PPC). Enjoy! Share! but don't sell/remarket!!! No affiliatiation with the US GOVT, state of California, LLNL or University of California....This is a gift from me to you; no warranty or support from me or anyone else- use at your own risk! Send me a postcard if you really like it! Dr. Michael Whitbeck L-369 Lawrence Livermore National Laboratory POB 808 Livermore, CA 94550 ------------ UPDATE / BUG FIX -------------- Note for release 3.2 (Mac version) of React React 3 has bugs! Sorry but it happens. React 3.2 is patched around the bug while I rethink the problem. News/warnings: Do not use the 'at' symbol [ '@' ] in variable names; it won't hurt anything but a future release may use this symbol for the user to flag variables to be treated using the steady-state approximation. Further news: watch for OS/2 and possibly DOS versions courtesy of George McBane