TSolMod:
C++ Class Library of Models of Mixing in PhasesSolutions
Predicting
the stability and thermodynamic properties of nonideal solution phases
over
wide ranges of pressure and temperature requires that theoretically
sound and
sufficiently accurate equation of state and activity models are used
within a
generalized GEM framework. The variety of such models calls for a
novel, flexible
and computationally efficient code architecture that supports diverse
solution
phase models with different mathematical structure and input data
setup. This was the main motivation for developing the TSolMod C++
class library for equation of state
and activity models, which ensures broad applicability of the GEM
software, in particular, GEMSelektor v.3 geochemical modeling package
and standalone GEMS3K code. Key innovative features
of the TSolMod library are:
 generic and flexible model
parameter setup;
 computationally efficient data
exchange with the GEM IPM equilibrium solver;
 open conceptual design that allows
straightforward extension to incorporate any
models for solution phases.
The current version of TSolMod library
features a
comprehensive selection of fluid, gas, liquid, and solid solution
models of
interest to a wide range of geochemical, petrological, material
science, and
chemical engineering applications.
More about TSolMod C++ class library can be learned from a
publication
 Wagner T., Kulik D.A., Hingerl F.F., Dmytrieva S.V.
(2012). GEMSelektor geochemical modeling package: TSolMod C++ class
library and data interface for multicomponent phase models. Canadian
Mineralogist 50, 11731195 (doi).
Contacts: Prof. Thomas
Wagner; Dr. Dmitrii Kulik
Overview of currently implemented activity and equation of state
models
Multicomponent fluids and gases
Model Name

Description

TSRKcalc 
SoaveRedlichKwong cubic
equation of state, with Van der Waals mixing rule using constant or
Tdependent parameter 
TPR78calc 
PengRobinson cubic equation
of state, with Van der Waals mixing rule using constant or Tdependent
parameter 
TPRSVcalc 
PengRobinsonStryjekVera
cubic equation of state, with Van der Waals mixing rule using constant
or Tdependent parameter 
TCORKcalc 
Compensated RedlichKwong
(CORK) hybrid cubic and virial equation of state, with Van Laar mixing
rule 
TSTPcalc 
SternerPitzer Helmholtz
energy based equation of state for highpressure systems, with Van Laar
mixing rule 
TCGFcalc 
Perturbation theory based
ChurakovGottschalk equation
of state, with basic Van der Waals mixing rul 
Liquid multicomponent nonelectrolyte solutions
Model Name 
Description 
TWilson 
Wilson local composition
activity model, with Tdependent nonrandomness parameter 
TNRTL 
Nonrandom twoliquid (NRTL)
local composition activity model, with Tdependent nonrandomness
parameter 
Multicomponent solid solutions
Model Name 
Description 
TIdeal 
Ideal mixing model for
fluid/gases and solidsolutions, supporting multisite ideal formalism
for solidsolutions 
TBerman

Microscopicinteraction
multisite model
for solidsolutions 
TRegular

Regular activity model of mixing
(symmetric formalism) 
TVanLaar 
Van Laar activity model
(asymmetric formalism) 
TRedlichKister 
Fourterm RedlichKister
activity model 
Ternary and binary solid solutions
Model Name 
Description 
TMargules

Ternary regular Margules
activity model 
TSubregular 
Binary subregular Margules
activity model 
TGuggenheim 
Binary 3term RedlichKister
activity
model 
Multicomponent aqueous electrolyte solutions (ionassociation)
Model Name 
Description 
TDebeyeHueckel 
Twoterm DebyeHueckel
equation model 
TLimitingLaw 
Oneterm DebyeHueckel limiting
law

THelgeson 
Extended DebyeHueckel equation
with common constant or TPdependent extended term parameter, and
common ion size 
TKarpov 
Extended DebyeHueckel equation
with common constant or TPdependent extended term parameter, and
individual ion sizes 
TShvarov 
Extended DebyeHueckel equation
with common constant or TPdependent extended term parameter, and
common ion size 
TDavies 
Davies equation form of the
extended DebyeHueckel
model 
Multicomponent aqueous electrolyte solutions (specific ion
interactions)
Model Name 
Description 
TSIT 
Twoterm Specific ion
interaction
(SIT) model 
TPitzer 
Pitzer (HarvieMollerWeare)
model with Tdependent binary and ternary interaction parameters 
TEUNIQUAC 
Extended UNIQUAC (Thomsen)
model with
Tdependent binary interaction parameter 
(always under construction)
For detailed description of calculations performed in
most TSolMod library models, see ActivityCoeffs.pdf
file from GEMSelektor documentation.
Last updated: 05.06.2021 DK
Copyright (c)
20122021 GEMS Development Team.