Multiple-Well, Multiple-Path Unimolecular Reaction Systems. I.MultiWell Computer Program Suite

摘要

UnimolecUlar reaction systems in which multiple isomers undergo simultaneou reactions via multiple decomposition reactions and multiple isomerization reactions are ( fundamental..interest in chemical kinetics. The computer program suite described here can b used to treat such coupled systems, including the effects of collisional energy transfer (wea collisions). The program suite consists of MultiWell.. which solves the internal energy mastE equation for complex unjmoecular reactions systems; DenSum, which calculates sums an densities of states by an exact-count method; Mom Inert, which calQulates externa.J principc moments of inertia and internal rotation reduced moments of inertia; and Thermo, whic] calculates equilibrium constants and other thermodynamics quantities. MultiWel1 utilizes , a hybrid master equation approach, which performs like an energy-grained master equation alow energies and a continuum master equation in the vibrational quasicontinuum. An adap tation of Gillespie's exact stochastic method is used for the solution. The codes are designe< for ease of use. Details are presented of various methods for treating weak collisions.witl virtually any desired collision step-size distribution and for utilizing RRKM theory for specifi, unimolecular rate constants.