chemical kinetics

*To*: mathgroup at yoda.physics.unc.edu*Subject*: chemical kinetics*From*: srandyt at circe.fr (Randall Thomas)*Date*: Mon, 27 Sep 93 11:00:23 +0200

Jean Peccoud writes :************* Does anybody have something (like a package) specially designed for chemical kinetics studies ? This could, for instance, generate the set of differential equations from the set of chemical reaction. *************************** I'm sure there are packages designed specifically for chemical kinetics, in fact I'm sure I've received ads for some, though I've since forgotten their names (shame on me). However, The generalized network simulator, SPICE, and especially its commercial version for all platforms, PSpice, are VERY convenient for many kinds of flow systems, compartmental systems, reaction/ diffusion coupling, epithelial transport, and, of course, chemical kinetics. It allows you to formulate the chemical reaction network as a set of coupled flow networks, specifying the constitutive relations (i.e. reaction kinetics of each step) as arbitrary functions of potentials (i.e., concen- trations, chemical potentials, ... votre choix) and/or flows (currents) elsewhere in the system. Very flexible. No need to set out the differential equations explicitly - SPICE solves the network using Kirchoff's Laws and nodal analysis (to say it simply!). Good numerics, even for stiff systems. The only hitch is that the most convenient variety, PSpice, has an engineer- oriented price-tag. Generic SPICE can be (or used to be) obtained free for mainframes and most workstations (anybody compiled it on a MAC or PC?), but requires the use of polynomials for definition of nonlinear constitutive relations. I recently bought NODAL in hopes it would do the same job in a more convivial and more democratic (because cheaper) environment, i.e., in Mathematica. UNFORTUNATELY, the "current- and voltage-controlled voltage or current sources" in Nodal are restricted to being linear (i.e., a constant multiplies a current or voltage), which makes it perfectly useless for the kinds of general system simulation (as opposed to electrical circuit simulation) that we do with (P)Spice. There may be a nonlinear version in the works (??). In France, PSpice is distributed by ATAC DIFFUSION, 3 rue du Marechal de Lattre de Tassigny, 78150 Le Chesnay, tel: (33-1) 39 63 20 76, fax: (33-1) 39 66 00 31. Ask for Mr. Chazarain. If you come to Paris, Mr. Peccoud, please look me up and we can talk about this over lunch. _____ Randall THOMAS INSERM U.323, CHU Necker 156, rue de Vaugirard 75730 Paris Cedex 15 tel: (1) 43 06 15 25 fax: (1) 40 61 55 91