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Paul Scherrer Institut PSI GEM-Selektor (GEMS-PSI) Home Page

Paul Scherrer Institut
5232 Villigen PSI, Schweiz/Switzerland
Tel. +41 56 310 21 11
Fax. +41 56 310 21 99



Updated:
26.10.2007
E-Mail: gems2.support@psi.ch


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GEMS Logo Welcome to GEM-Selektor (GEMS)

Research package for thermodynamic modelling of aquatic (geo)chemical systems by Gibbs Energy Minimization

The GEMS code package offers high chemical plausibility of equilibrium thermodynamic models

  • Stable and metastable minerals are selected using rigorous phase stability criteria
  • Aqueous - solid solution equilbria may involve many (non)ideal solid or liquid solutions, gas mixture and/or non-ideal fluids
  • Multi-site-surface complexation on mineral-water interfaces can be computed in elemental stoichiometry, without site balances
  • (Ad)sorption models can be considered together with other solution phases
  • Redox state is calculated from the bulk chemical composition of the system
  • Processes of irreversible chemical mass transfer can be simulated using principles of local and partial equilibrium
  • Thermodynamic data are automatically corrected for temperature and pressure
  • Various inverse (geo)chemical problems can be solved
  • and much more...

The complexity of chemical system setup is limited mainly by the availability of thermodynamic data for species and phases. A default thermodynamic database is the Nagra/PSI chemical thermodynamic data base 01/01, enhanced with the imported SUPCRT database. Third-party databases for specific applications, for instance for cements, will be available soon  in GEMS format (see Latest News).

To learn quickly how to work with the user-friendly GEMS code:

  •  download it; install; in your web browser, click on the "Online Tutorial" link to the left, and run the code in parallel with reading the Screenshot Tutorial.

If you  experience problems, please go to a "Support" link and send us a bug report form.

GEMS software package is distributed "as is" by the Laboratory for Waste Management (LES) of the Paul Scherrer Institute (PSI) with two purposes:

  • to promote the GEM method and software into a worldwide academic research community;
  • to gather the users feedback - vital for making the software functional and reliable.
Permission to use the GEM-Selektor software is hereby granted free of charge for educational and academic research purposes, subject to Terms and Conditions of Use.

GEMS Development and Support Team

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