GEMS Development Team
GEM Software is developed since 1996 (since 2000 at PSI). Since March
2008, GEMS is developed jointly by the PSI team (D. Kulik, S. Dmytrieva,
G. Kosakowski, S.Nichenko) and by the ETHZ team (G. Dan Miron, now at PSI
LES; Allan Leal); T. Wagner (now at RWTH Aachen) actively used and
improved GEMS since mid-2004; A.Gysi (Colorado School of Mines) is
co-developing GEM2MT module and providing MINES TDB for modelling
hydrothermal rock alteration and ore formation.
A. Kulik, team leader (Paul
Scherrer Institut): responsible for theoretical and practical
development of GEM IPM algorithm, its accuracy and phase stability
criteria; general design of GEM-Selektor
and GEMS3K codes, documentation, help,
web pages; co-development of TSolMod
class library of built-in models of mixing in phases-solutions;
lead of Nanocem CemGEMS
web app project; co-development of the GEMSFIT code and architect of the ThermoEcos
Svitlana V. Dmytrieva (now at Cosylab
CH) wrote the database management, script interpreter, process
simulator, GtDemo sampler and many other modules of Selektor-A code in
1991-1996. She re-wrote Selektor-A code from C into the GEM-Selektor code
in C++ in 1996-2002. At present, she maintains and develops the GEM-Selektor
GUI based on the Qt UI framework. She is also
involved in optimization and improvement of GEMS3K
and GEMSFIT codes.
Dan Miron (Paul Scherrer Institut), since September 2012 main
developer of GEMSFITS codes and
since 2020 leading the ThermoEcos
project. In particular, the code functionality is extended to fitting not
only interaction parameters of mixing in non-ideal phases, but also
thermodynamic properties of phase components, as well as inverse
titrations, thermobarometry and other applications. He is also the main
force in developing ThermoHub database and its client libraries ThermoFun
and ThermoMatch as a foundation for future versions of GEMS.
P. Gysi (Bureau of Geology and Mineral Resources, New Mexico Tech,
USA), leading expert in geochemistry of hydrothermal ore deposits,
thermodynamics of fluid-mineral equilibria, experiments and numerical
modeling of hydrothermal fluid-rock interaction. He is a GEMS enthusiast,
since 2012 contributing with tutorials, testing and applications of GEMS
codes. He is providing MINES
TDB as a plugin for GEM-Selektor for modelling hydrothermal rock
alteration and ore formation. He also is co-developing the GEM2MT module
for simple geochemical reactive transport simulations such as sequential
reactors chain, box-flux chain, and 1-D column
Allan M.M. Leal
(ETHZ IG GEG), the author of novel, robust and efficient equilibrium
methods and reactive transport solvers implemented in the Reaktoro
framework for modeling reactive chemical systems. He participates in
developing the next-generation numerical kernel xGEMS for GEM Software,
achieved by combining GEMS3K and Reaktoro
codes with novel client libraries ThermoFun and ThermoSol.
(Paul Scherrer Institut) is an expert in geochemical modeling and
thermodynamic databases, in particular, one of authors of Nagra-PSI
01/01 database. He maintains the default
'Kernel' Nagra-PSI default chemical thermodynamic data base distributed
with the GEM-Selektor package.
Sergii Nichenko (Paul
Scherrer Institut): works on thermodynamic modeling of nuclear materials,
in particular complex mixed systems such as nuclear fuels and molten
salts, as well as evaluation of thermophysical and thermodynamic
properties by MD/MC(molecular dynamics - Monte Carlo) methods. He is
developing ThermoSol - a new version of TSolMod library for activity
models of phases-solutions. He is also maintaining the HERACLES
database in GEM-Selektor format. This database for nuclear
engineering applications is available as a GEMS3 default database plugin.
Wagner (now at IML RWTH Aachen), an expert in geochemistry of ore
deposits and geochemical thermodynamics. His main interest lies in
thermodynamically consistent implementation of complex non-ideal solution
models for rock-forming minerals, fluids,and ore minerals, as well as in
methods of T-P correction of thermodynamic data and in advanced
applications of thermodynamic modeling in hydrothermal ore geochemistry.
T.Wagner used to be a co-developer of GEM algorithms and GEM-Selektor
code, and a leading developer of the TSolMod
class library of built-in models of mixing in phases-solutions.
Kosakowski (Paul Scherrer Institut), leading expert in
hydrogeochemical mass transport modelling. He participates in development
of GEMS3K code, especially its interface for data exchange within coupled
reactive transport codes, in particular OpenGeoSys-GEMS. His contribution
was crucial in dramatic improvement of stability and precision of GEMS3K.
Lothenbach (EMPA, Switzerland),
leading expert in thermodynamic modeling of cement hydration and
degradation. Maintains and distributes Cemdata - a thermodynamic database
for cement systems in GEM-Selektor format. This database is available as a
GEMS3 default database plugin at http://www.empa.ch/cemdata.
Yapparova (ETHZ IGP, Switzerland) develops and applies the coupled
code CSMP++GEM, which uses the (parallelized) GEMS3K kernel code for
simulations of 1-D and 2-D reactive transport in geothermal systems with
water-rock interaction, boiling and condensation phenomena included. She
is also interested in reactive transport modelling of hydrothermal
dolomitization (the topic of her PhD thesis).
Ravi A. Patel
(PSI LES) is an expert in Lattice Boltzmann methods of reactive transport
modelling at pore scale. He develops and maintains the Yantra
open source code, recently coupled with PHREEQC and xGEMS (GEMS3K)
chemical solvers. As Yantra is a Python code, together with Allan Leal and
G. Dan Miron, he developed a Python interface for GEMS3K as part of the
Implementation of GEM-Selektor and GEMS3K codes would not have been
possible without people who contributed much to development of the
preceding Selektor-A code and thermodynamic database:
(Geowissenschaften, JOGU Mainz, Germany): Improvement of the GEM2MTmodule
of GEM-Selektor for 1-D coupled reactive
Churakov (Paul Scherrer Institute): Supplied the source C++ code
ofChurakov-Gottschalk EoS for gas/fluid mixtures, adapted as part of the TSolMod
(Paul Scherrer Institut) is a leading expert in thermodynamic modeling of
radionuclide solubility limits in cement, clay and other aquatic systems
of relevance for radioactive waste management. He is themain peer in
testing new functionality of GEMS and defining roadmaps of its future
Shcherbina (now at Forschungszentrum Julich): expert in
thermodynamic modeling of solid-gas systems related to nuclear materials.
She started compiling the HERACLES
database in GEM-Selektor format.
Chudnenko (Institute of
Geochemistry, Irkutsk, Russia) created earlier SELEKTOR codes for
IBM/360 compatible mainframes and maintains the alternative Selektor-W
code that use the same GEM IPM algorithms but have different format of
thermodynamic database and text-based user's interface. He contributed a
lot in incorporating the proprietary IPM modules into Selektor-A codes in
1990-1996, and upgrading it into a high-precision IPM-2 module of
GEM-Selektor in 2000-2001.
Igor K. Karpov (Institute of Geochemistry, Irkutsk, Russia), creator of
the convex programming GEM approach (theoretical development, algorithms,
applications, scientific mentorship). In early 1970s he initiated
the development of SELEKTOR codes and promoted this technique over 30
years, leading the Laboratory
for Physicochemical Modeling. Prof. Karpov passed away in March
2005; the Laboratory is headed by Prof. K.Chudnenko.
Andriy V. Rysin designed module
window/page screen forms and many other GUI elements in Linux version of the
GEM-Selektor code. In 2001-2002, he connected these windows and dialogs to
the Qt UI Toolkit, ported GEMS to various platforms, designed an improved
GraphDialog and other user-interface utilities.
Vasilii A. Sinitsyn (Kyiv
State University, Ukraine) in 1990-1996 took part in in inplementation of
modules for calculation of thermodynamic data and development of DComp and
ReacDC formats in Selektor-A code. He also contributed to compilation of
thermodynamic database and performed many modeling applications.
Gottschalk (GFZ Potsdam, Germany): Conversion of a chemical
thermodynamic database for metamorphic minerals and fluids into
GEM-Selektor format (in 2004-2005).
F. Hingerl (ETH Zurich and PSI, since August 2012 at ERE,
Stanford University, USA) from 2008 to 2012 contributed in extending TSolMod
and GEMS3K codes with Pitzer, Extended
UNIQUAC, and rEUNIQUAC models for concentrated aqueous electrolytes over
wide ranges of temperature and pressure (in association with the CCES
GEOTHERM project). SInce 2010 until mid-2012 he has been develooping
the GEMSFIT parameter fitting code for aqueous activity models.
Damiani (PSI LES), in his PhD project (2015-2018) investigated
reactive transport by diffusion of charged aqueous species using
Nernst-Planck equation and Donnan approach. Codes that he implements
include coupling of GEMS3K and Reaktoro with FeniCS and applications to
radionuclide and hydrogen transport in clays and clay rocks.
Mykhailo .S. Khodorivski (Kyiv) has translated SUPCRT92 subroutines from
fortran to C and built them into Selektor-A package in 1991-1993.
Yuri A. Shybetsky (Kyiv)
in 1996-1997 has extended Selektor-A and its thermodynamic database
to isotopic systems and worked on analysis and propagation of the
uncertainty of thermodynamic data.
Irina L. Kolyabina
(Institute of Environmental Geochemistry, Kyiv) in 1996-1999 worked on
extension of the Selektor-A built-in thermodynamic database.
Tanya Peretyazhko (now in Houston, USA) helped us in 1997-1999 at SSE
Technocentre, Kyiv to test and set up surface complexation models in GEM
implementation and to compare them with LMA (FITEQL3) results.
DK wishes to thank Prof. V.B.Koval, Prof. E.V. Sobotovich, Prof.
V.V.Tokarevsky; Dr. M.S.Khodorivsky and Dr. V.A.Sinitsyn for the
administrative help and support during his terms in Kyiv institutions (SSE
Technocentre, Institute of Environmental Geochemistry). He thanks many
colleagues and students for discussions and criticism related to earlier
versions of GEM-Selektor codes.
Further, DK thanks Prof. Jan Harff (Institute for Baltic Sea Research,
Warnemuende, Germany) for constructive support during his work there in
1992-1993 and 1998; to Prof. S.U.Aja (Brooklyn College of CUNY) for his
support while hosting DK and VS during their NAS/NRC OCEE exchange visits
in 1996-1997. Special thanks are to Prof.
Kersten (Johannes-Gutenberg University, Mainz) for quite productive
collaboration since 1997 on many SSAS modeling topics, promotion of GEMS
development, and purchase of the first Qt professional license.
DK and SD also acknowledge the friendly and constructive help from Drs.
U.Berner, E.Curti, W.Hummel, T.Thoenen, and other people at LES PSI during
research visits in Spring 1999, resulted in the development of PM2SEL
utility program, and their continuous support of GEMS development since
June 2000. Finally, we are grateful to Dr. V.A.Pokrovskii for sending us
the SUPCRT92 program and to Prof. D.A.Sverjensky (Johns Hopkins
University, Baltimor, USA) for providing the PRONSPREP97 code.
Parts of work on GEMS development have been indirectly supported since
1990 through a number of research grants from the Ukrainian Foundation for
Basic Research, Ministry of Chornobyl (Ukraine), International Science
Foundation, Deutsche Forschungsgemeinschaft, European Science Foundation,
NAS/NRC OCEE Radioactive Waste Program, and other public non-commercial
sources. Since June 2000, development of GEMS code has been taken
over by the Waste Management Laboratory of the Paul Scherrer Institute;
constructive help of the Laboratory Heads, Dr. J.Hadermann and Dr.
M.Bradbury, and partial financial support from Nagra are gratefully
Last but not least, the Team is grateful to Dr.
Gillian Gruen (focusTerra, ETH Zurich) for professional design of an
exciting set of icons used in GEM-Selektor Graphical User Interface and on
GEMS help and web pages.
GEMS Development Team acknowledges recent and on-going support that comes
from various sources, among others:
National Cooperative for the Disposal of Radioactive Waste), Wettingen;
project of the Competence Center Environment and Sustainability of
the ETH Domain (CCES) (2008-2012);
of the European Atomic Energy Community's Seventh Framework
Programme FP7 (2011-2013);
Fluid chemistry and fluid-rock interaction of
Alpine veins, Central Alps (T.Wagner, SNF funded);
Internally-consistent thermodynamic data for
fluid-rock equilibria: Development and applications (T.Wagner, ETHIIRA
SNF Sinergia project "Stable phase composition
in novel cementitious systems: C(-A)-S-H"
SNF Sinergia project "COTHERM - COmbined
hydrological, geochemical and geophysical modelling of geotTHERMal
SNF CASH-2 project (on-going).
History of Development
GEM-Selektor belongs to a SELEKTOR family of program codes that implement a
convex programming approach to Gibbs energy minimization calculations of
chemical thermodynamic equilibria, developed since 1974 in the laboratory of
Prof. Igor K.Karpov at the A.P.Vinogradov Institute of Geochemistry,
The first Selektor code (based on a combination of "steepest descent" and
Newton minimization algorithms) for BESM-6 mainframes appeared in 1975.
Since then, the code was used in many academic institutions in the
former USSR to solve chemical equilibrium problems in various scientific
and applied fields. The modern IPM minimization algorithm has been
developed by I.K.Karpov, V.A.Detkovskaya and K.V.Chudnenko in 1984-1988.
At the same time, a Selektor-3 code has been re-written in PL/1 for
IBM-360 compatible mainframes.
An interactive concept for Selektor implementation on PC was suggested by
D.Kulik in 1990, when a collaboration between his group at the academic
Institute of Geochemistry and Mineral Physics, Kyiv (Ukraine) and Prof.
Karpov's laboratory (Irkutsk, Russia) was established. Since then (in
1991-1999), D.Kulik's group at the Environmental Radiogeochemistry Centre
and the SSE Technocentre, Kyiv, Ukraine (S.Dmitrieva), collaborated in the
development and application of SELEKTOR codes.
These activities became even more international since 1992, supported in
part through several research grants (International Science Foundation,
Deutsche Forschungsgemeinschaft, European Science Foundation, NAS/NRC OCEE
Radioactive Waste Program) and scientific excahnge programs for D.A.Kulik
(at Institute for Baltic Sea Research Warnemuende,Rostock; University of
Bonn; J.Gutenberg University, Mainz, Germany; Brooklyn College of CUNY,
USA; Paul Scherrer Institute, Switzerland). Most of this support was
aimed at development of geochemical modeling applications in marine- and
environmental geochemistry; naturally, this work gave important feedback
and ideas for improvement and further development of software and
thermodynamic database. This work has also resulted in an extension of
GEM technique to surface complexation on mineral-water interfaces
(Kulik, 2000, 2002, 2006), which has been implemented since 1995 in
Selektor-A and GEMS version 1 codes.
Since June 2000, the development of GEMS code has been taken over by the
Waste Management Laboratory at the Paul Scherrer Institute (Switzerland)
in continuing collaboration with Prof. Karpov's laboratory and SSE
Technocentre, Kiev (S.Dmitrieva). in 2001, the GEM IPM module
(numerical "engine" of Selektor codes) has been upgraded into an
IPM-2 module, yielding a 9 order of magnitude gain in the mass-balance
precision of GEM technique, which made it possible to use GEM in most
demanding geochemical applications involving trace elements and
radionuclides. The IPM-2 module, together with an improved graphical
user's interface powered by the Qt Toolkit, forms a basis of GEM-Selektor
v.2-PSI program package.
The first release of the GEMS-PSI version 2.0 code with built-in edition
of NAGRA-PSI thermochemical database, oriented mainly to aquatic systems
and applications in performance assessment in radioactive waste disposal,
took place by the end of 2003 on this web site (https://gems.web.psi.ch/).
Since 2008, the GEM-Selektor code is developed jointly by the PSI LES and
the ETHZ IGP teams. The emphasis of PSI team is in modeling applications
of GEMS and GEMS3K (formerly GEMIPM2K) for scientific issues related to
nuclear waste disposal. The emphasis of IGP team is in modeling
applications of both codes in various areas of hydrothermal ore
geochemistry and geothermal research. Conversely, this collaborative
development is expected to lead to much broader acceptance of GEM-Selektor
in geochemical research community. These efforts led to even more stable
and precise GEM IPM algorithm, as well as introduction of the TSolMod
class library and data interface for built-in models of mixing of
phases-solutions. The present GEM-Selektor v.3 and GEMS3K codes comprise
the outcome of these efforts.
Since 2013, after Prof. T.Wagner move to University of Helsinki (UH),
Finland, GEM Software is developed jointly by PSI LES, UH and ETHZ
IGP teams. Later (in 2018), Prof. Wagner moved to RWTH Aachen (Germany).
Since 2012, Prof. A.P.Gysi (Colorado School of Mines) is actively
promoting GEMS in hydrothermal geochemistry and ore formation application,
in form of classes, MINES TDB and co-development of the GEM2MT module of
Last updated: 19.05.2019
(c) 2003-2020 GEMS Development Team