Global Utilities

RRKM Programs for the Macintosh


Two programs are available if you contact me by E-mail. They are offered on the understanding that they are non-commercial, and still under development. I am reluctant to part with source listing files, but might do so if you spin me a good story. There is no guarantee that either program is either accurate or harmless to your computer system, though I personally believe them to be both.

Both programs address the calculation of dissociation rates of isolated molecules or ions with fixed internal energy. Neither includes the facility for integrating over collisions to obtain k(T) as would be required in a typical gas kinetics application.


'RRKM large' specifications:
Up to 1000 atoms maximum. Up to 41 eV maximum internal energy. Only deals with harmonic oscillators; internal rotors must be entered as low frequency harmonic vibrations. Uses Beyer-Swinehart state counting, with all energies expressed as integer multiples of a 25 cm-1 unit. Calculates k(E), and kinetic energy release distribution (rather crudely), including the possible effects of a rotational reverse critical energy barrier, and the possibility that modes other than the reaction co-ordinate contribute to the kinetic energy. Restricted to a fixed internal energy. Fairly well documented.

'RRKM small' specifications:
Up to 50 atoms maximum. Up to 4 eV maximum internal energy. Allows harmonic oscillators, and both free and hindered internal rotors. Uses Beyer-Swinehart state counting with a 1 cm-1 energy unit. Calculates k(E), Boltzmann internal energy distributions, and kinetic energy release distribution. The KERD allows for rotational barrier, initial state distributions based on Boltzmann populations, time window selection, or both. At this stage it does not consider the possibility of contribution from modes other than the transition state reaction co-ordinate. No documentation as yet.

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Last Updated: 18 January, 2006