University of MichiganAnn Arbor, MI 48109-2143

Climate and Space Sciences and Engineering

MultiWell Program Suite

J. R. Barker, T. L. Nguyen, J. F. Stanton, C. Aieta, M. Ceotto,
F. Gabas, T. J. D. Kumar, C. G. L. Li, L. L. Lohr, A. Maranzana,
N. F. Ortiz, J. M. Preses, J. M. Simmie, J. A. Sonk, and P. J. Stimac


This is the MultiWell web site. Contact John R. Barker at for further information or to be added to the email list.

NEW IN VERSION 2020.3 (Oct 2020)

1. COVID-19: Because of COVID-19, access to the computer that supports the MultiWell website was restricted and we distributed interim versions of the MultiWell package informally. The revisions were needed, because we had problems with correctly compiling the Windows versions and because we had increased the default sizes of some arrays, which made the codes too large to handle on some Users' computers. Here were the substantive changes retained in the present version:

  • in v. 2020.2, we corrected a bug discovered by Gabe Da Silva and his student Milad Marinami. The bug affected calculations that invoked the Eckart tunneling feature when computing canonical transition state theory rate constants. The affected only the 2020 version of THERMO.
  • The default maximum number of degrees of freedom was increased from 50 to 100. This means that every species (reactants, products, and trial transition states) can have as many as 100 entries for internal degrees of freedom (vibrations, internal rotations, hindered rotors). In all other respects, the code is the same as the 2020 version.

2. MultiWell Master Equation Code: New Feature: 'BIMOLRXN': This option can be invoked for canonical (i.e. thermal) bimolecular reactions of a Well with the bath gas. The canonical rate constant, which is expressed with Arrhenius parameters: kbim(T) = Afc × exp(–Bbm/T), where T is the translational temperature. This feature is useful for bimolecular reaction rate constants that do not have significant dependence on the internal energy of the Well (i.e. kbim(E) for the bimolecular reaction is approximately constant, as in the work of Matthias Oltzmann (2002)). When the energy dependence cannot be neglected, the BIMOLRXN option should not be used, but the microcanonical kbim(E) can be computed and entered as an external RKE type file, as already described in the User Manual.

3. MultiWell User Manual: Updated for v.2020.3.