DEWPython is a Python implementation of the Deep Earth Water (DEW) model that allows users to compute thermodynamic and elastic properties of various aqueous species across a wide range of temperatures (100-1200°C) and pressures (1-60 kbar). The package is based on the DEW spreadsheet and provides similar functionality with enhanced features, including integrated SUPCRT support.
DEWPython calculates Gibbs energies of formation, equilibrium constants, and standard volume changes for reactions in extreme pressure-temperature conditions, making it particularly valuable for modeling geochemical processes in planetary interiors, hydrothermal systems, and deep-Earth environments.
Because two flavors of SUPCRT are also implemented, DEWPython can calculate thermodynamic properties down to 1 bar and 273 K.
- Calculate thermodynamic properties across extreme pressure-temperature ranges
- Integrated support for SUPCRT96 and SUPCRTBL directly within the package (executables included)
- Import and compare species between DEW and SUPCRT models
- Built-in database of minerals and aqueous species from slop16.dat (thermodynamic datafile from Shock et al., including many organic compounds)
- Interactive and automated input options
- Plotting utilities for visualizing thermodynamic properties
DEWPython has been successfully applied to studying:
- Thermodynamic constraints on the citric acid cycle and related reactions in ocean world interiors
- Chemical reaction networks in extreme environments
- Stability of organic compounds under high pressure-temperature conditions
- Biogeochemical processes relevant to astrobiology and prebiotic chemistry
pip install DEWPythongit clone https://github.com/mmelwani/DEWPython.git
cd DEWPython
pip install -e .import DEWPython
from DEWPython import DEWModel as dm
# Initialize a DEW object
reaction = dm.DEW()
# Define temperature and pressure arrays
pt_arr = [[100, 1000, 10], [1, 60, 1]] # [T_min, T_max, T_step], [P_min, P_max, P_step] (°C, kbar)
# Run calculation with automatic inputs
reaction.run(pt_arr,
min_inp=[],
aq_inp=[['CO2,AQ', '4'], ['H2,aq', '5']],
g_inp=[],
h2o_inp=0,
min_out=[],
aq_out=[['Oxaloacetate2-', '1'], ['H+', '2']],
g_out=[],
h2o_out=3,
ptInp='Regular',
rhoWat='Z&D 2005',
forceBool=False,
dieEQ='Sverjensky',
forceSC=True,
WFEQ='D&H 1978',
dsV=False,
pdsV=False,
DV=False)
# Export results to CSV
reaction.export_to_csv()DEWPython includes built-in SUPCRT functionality with both SUPCRT96 and SUPCRTBL executables packaged within the distribution:
import DEWPython
from DEWPython import DEWModel as dm
# Initialize a DEW object
reaction = dm.DEW()
# Run SUPCRT interactively
reaction.run_supcrt() # Uses SUPCRT96 by default
# Or specify version
reaction.run_supcrt(version='96') # SUPCRT96 - supports Maier-Kelly heat capacity and Powell & Holland 1990 equations
# reaction.run_supcrt(version='BL') # SUPCRTBL - includes updated thermodynamic dataset with Holland & Powell (2011) properties
# Process SUPCRT output
reaction.calculate_supcrt(customFile="output_file.out")
# Export processed SUPCRT results
reaction.export_supcrt_to_csv()DEWPython includes multiple SUPCRT variants:
-
SUPCRT96: An improved version of SUPCRT92 (Johnson et al., 1992) that supports both Maier-Kelly heat capacity expressions (Cp = a + b·T + c·T⁻²) and the four-term Powell & Holland (1990) equation (Cp = a + b·T + c·T⁻² + d·T⁻⁰·⁵)
-
SUPCRTBL: A further enhanced version (Zimmer et al., 2016) that updates the thermodynamic dataset with:
- Properties from Holland & Powell (2011) for mineral end-members
- Added As-acid and As-metal aqueous species
- Updated properties for Al-bearing species and other minerals relevant to geological carbon sequestration
While not directly integrated into DEWPython, these complementary tools are often used alongside it for comprehensive thermodynamic modeling:
- SeaFreeze: A separate package for calculating thermodynamic properties of ice polymorphs (Ih, II, III, V, VI and ice VII/ice X) and liquid water at conditions relevant to ocean worlds (130-500 K, 0-2300 MPa). SeaFreeze can be used to determine water phase boundaries when modeling planetary interiors. Available at github.com/Bjournaux/SeaFreeze.
DEWPython can be used interactively, prompting for inputs:
reaction = dm.DEW()
reaction.set_inputs() # Set input species
reaction.set_outputs() # Set output species
reaction.set_preferences() # Set calculation options
reaction.set_TPRho() # Set temperature and pressure conditions
reaction.calculate() # Perform calculations
reaction.make_plots() # Generate plotsFor automated or scripted use:
reaction = dm.DEW()
reaction.run(pt_arr, min_inp, aq_inp, g_inp, h2o_inp, min_out, aq_out, g_out, h2o_out,
ptInp, rhoWat, forceBool, dieEQ, forceSC, WFEQ, dsV, pdsV, DV)To find available species in the database:
dm.search("string") # Search for species containing "string"The following example models the formation of oxaloacetate from CO₂ and H₂ under conditions relevant to ocean worlds:
import DEWPython
from DEWPython import DEWModel as dm
import numpy as np
# Initialize model
reaction = dm.DEW()
# Define PT conditions relevant to ocean worlds (e.g., Enceladus)
pt_arr = [[100, 500, 20], [1, 10, 1]] # [T_min, T_max, T_step], [P_min, P_max, P_step]
# Run calculation
reaction.run(pt_arr,
min_inp=[],
aq_inp=[['CO2,AQ', '4'], ['H2,aq', '7']],
g_inp=[],
h2o_inp=0,
min_out=[],
aq_out=[['Oxaloacetate2-', '1'], ['H+', '2']],
g_out=[],
h2o_out=3,
ptInp='Regular')
# Export results
reaction.export_to_csv()The DEW model extends the Helgeson-Kirkham-Flowers (HKF) equations of state to calculate thermodynamic properties at high temperatures (373-1473 K) and pressures (0.1-6 GPa). DEWPython implements:
- Water density calculations using Zhang & Duan (2005, 2009)
- Dielectric constant calculations using multiple equations (Johnson & Norton, Franck, Fernandez, Sverjensky)
- Gibbs free energy calculations using Delaney & Helgeson (1978) or numerical integration
- Born coefficients for aqueous species
These calculations enable accurate prediction of reaction properties under extreme conditions relevant to planetary interiors and deep-Earth environments.
| Model | Pressure Range | Temperature Range | Integration Status |
|---|---|---|---|
| DEW | 0.1-6 GPa | 373-1473 K | Core functionality |
| SUPCRT96 | 0.0001-0.5 GPa | 273-873 K | Integrated in package |
| SUPCRTBL | 0.0001-0.5 GPa | 273-1273 K | Integrated in package |
| SeaFreeze | 0.0001-2.3 GPa | 130-500 K | Separate complementary tool |
Recent work by Işık et al. (2025) has applied DEWPython to study thermodynamic constraints on the citric acid cycle and related reactions in ocean world interiors. This research demonstrated the feasibility of using DEWPython to:
- Quantify the thermodynamic viability of metabolic reactions under pressure-temperature conditions in ocean worlds
- Calculate equilibrium constants and Gibbs free energy changes for reactions in the TCA cycle
- Model prebiotic reaction networks at high pressures
- Identify potential energy bottlenecks in metabolic pathways on different planetary bodies
In this research, SeaFreeze was used as a complementary tool to determine water phases along PT profiles, helping to exclude icy regions from calculations for aqueous species.
- Pandas
- NumPy
- Matplotlib
- Collections
- JSON
- Huang, F., & Sverjensky, D. A. (2019). Extended Deep Earth Water Model for predicting major element mantle metasomatism. Geochimica et Cosmochimica Acta, 254, 192-230.
- Sverjensky, D. A. (2019). Thermodynamic modelling of fluids from surficial to mantle conditions. Journal of the Geological Society, 176(2), 348-374. https://doi.org/10.1144/jgs2018-105
- Facq, S., Daniel, I., Montagnac, G., Cardon, H., & Sverjensky, D. A. (2016). Carbon speciation in saline solutions in equilibrium with aragonite at high pressure. Chemical Geology, 431, 44-53.
- Johnson, J.W., Oelkers, E.H. & Helgeson, H.C. (1992). SUPCRT92 - A software package for calculating the standard molal thermodynamic properties of minerals, gases, aqueous species, and reactions from 1 bar to 5000 bar and 0°C to 1000°C. Computers and Geosciences 18:899-947.
- Sverjensky, D. A., Harrison, B., & Azzolini, D. (2014). Water in the deep Earth: The dielectric constant and the solubilities of quartz and corundum to 60 kbar and 1200°C. Geochimica et Cosmochimica Acta, 129, 125-145.
- Işık, S., Melwani Daswani, M., Işık, E., Weber, J., & Olgun Kıyak, N. (2025). Thermodynamic constraints on the citric acid cycle and related reactions in ocean world interiors. ACS Earth & Space Chemistry, in press (arXiv e-print: astro-ph.EP)
- Chan, A., Melwani Daswani, M., Vance, S. (2020). DEWPython: A Python Implementation of the Deep Earth Water Model and Application to Ocean Worlds.
- Zimmer, K., Zhang, Y.L., Lu, P., Chen, Y.Y., Zhang, G.R., Dalkilic, M. & Zhu, C. (2016). SUPCRTBL: A revised and extended thermodynamic dataset and software package of SUPCRT92. Computer and Geosciences 90:97-111.
- Journaux, B., Brown, J.M., Pakhomova, A., Collings, I.E., Petitgirard, S., Espinoza, P., Boffa Ballaran, T., Vance, S.D., Ott, J., Cova, F., Garbarino, G., Hanfland, M. (2020). Holistic Approach for Studying Planetary Hydrospheres: Gibbs Representation of Ices Thermodynamics, Elasticity, and the Water Phase Diagram to 2,300 MPa. Journal of Geophysical Research: Planets, 125, e2019JE006176.
- Holland, T.J.B. & Powell, R. (2011). An improved and extended internally consistent thermodynamic dataset for phases of petrological interest, involving a new equation of state for solids. Journal of Metamorphic Geology, 29, 333-383.
- Mohit Melwani Daswani (PI) - Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
- Seda Işık - Eurasia Institute of Earth Sciences, Istanbul Technical University, 34469 Istanbul, Türkiye
- Emre Işık - Max Planck Institute for Solar System Research, 37077 Göttingen, Germany
- Andrew Chan (Former Caltech SURF student intern at JPL) - Div. of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA 91125 (Graduated and no longer affiliated to Caltech.)
- Steven Vance - Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
Copyright (C) 2025 Jet Propulsion Laboratory, California Institute of Technology. Government sponsorship acknowledged.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
M.M.D. was supported by the NASA Planetary Science Early Career Award Program NNH19ZDA001N-ECA to proposal #19-ECA19-0032. A part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). Financial support for A.C. was provided by the Jet Propulsion Laboratory, California Institute of Technology Summer Undergraduate Research Fellowship program, and the Caltech Associates. S.I. acknowledges funding by the Scientific and Technological Research Council of Türkiye (TÜBITAK), under grant 122F287.
V 2.0.1
Automatic input function updated (2022/10/30). Now you can use it in the form as shown in tools/Example-dew-calc.ipynb. Beware: this is a beta release. You can use it only by cloning this repository into your local disk, then importing DEWPython according to the location of the cloned repository.
V 2.0.0
The DEW package allows the user to compute the thermodynamic and elastic properties of various aqueous inputs for a general range of 100 - 1200 C and a pressure range of 1 - 60 kbar. It is based on the DEW spreadsheet and behaves similarly. The DEW package additionally provides integrated support for SUPCRTBL and can be used to directly import and compare species between the two models.