*** SOFTWARE RELEASE ANNOUNCEMENT ***
MultiWell, version 1.01
November 1999
Free Source Code
Macintosh and Unix/Linux versions are currently available. This
version includes minor bug fixes and clearly stated copyright
information. If you down-loaded the first release (v 1.0), please
discard it and download this version in its place. Up-dated versions
will be posted periodically.
With minor revisions, the source code can be compiled on other
platforms (e.g. Windows). Compressed files can be downloaded from the
MultiWell web site.
MultiWell web site: http://aoss.engin.umich.edu/multiwell/
MultiWell calculates time-dependent concentrations, yields,
vibrational distributions, and rate constants as functions of
temperature and pressure for unimolecular reaction systems which
consist of multiple stable species, multiple isomerization reaction
channels interconnecting them, and multiple fragmentation channels
from each stable species. The stochastic method is used to solve the
resulting Master Equation. Users may supply unimolecular reaction
rate constants (k(E)'s), sums of states and densities of states (for
RRKM theory), or optionally use the Inverse Laplace Transform method.
Users can select for weak collision effects different collision
models for down-steps including exponential, biexponential,
generalized exponential, etc., and user-dẽned functions. Thermal,
chemical activation, or user-defined functions can be used for the
initial energy distribution.
The code is intended to be relatively easy to use. It is designed so
that very complicated and very simple unimolecular reaction systems
can be handled via the data ̃le: no restructuring of the code or
recompiling is necessary to handle even the most complex systems.
MultiWell is most suitable for time-dependent non-equilibrium
systems. The real time needed for a calculation depends mostly upon
the number of collisions during a simulated time period and on the
number of stochastic trials needed to achieve the desired precision.
For slow reaction rates and precise yields of minor reaction
products, the code will require a long run time, but it will produce
results. For long calculation runs, we often just let it run
overnight.
MultiWell is a new code (1999) based on the Gillespie Exact
Stochastic algorithm [1], as developed in our laboratory [2]. It will
be described much more fully in a future publication.
For more information, see the MultiWell web site, or contact me.
-John R. Barker
[log in to unmask]
[1] (a) D. T. Gillespie, J. Comput. Phys. ,1976, 22, 403;
(b) D. T. Gillespie, J. Phys. ,1977, 81, 2340;
(c) D. T. Gillespie, J. Comput. Phys. ,1978, 28, 395.
[2] (a) J. R. Barker, Chem. Phys., 77, 201 (1983).
(b) J. Shi and J. R. Barker, Int. J. Chem. Kinetics, 22, 187 (1990).
(c) J. R. Barker, J. Phys. Chem., 96, 7361 (1992).
(d) J. R. Barker and K. D. King, J. Chem. Phys., 103, 4953 (1995).
_________________________________________________________
John R. Barker Department of Atmospheric, Oceanic, and Space Sciences
& Department of Chemistry
1520 Space Research Building
University of Michigan Tel: 734-763-6239
2455 Hayward Street Fax: 734-764-5137
Ann Arbor, MI 48109-2143 (USA) [log in to unmask]
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