UCLCHEM 4.0: An open source gas-grain astrochemistry simulation framework
Abstract
Astrochemical modelling is a key tool for interpreting the formation and destruction of molecules in the interstellar medium, complementing the increasingly detailed observations enabled by modern day observational facilities. UCLCHEM is a comprehensive gas-grain astrochemical modelling framework that can compute the chemical evolution inside a parcel of gas and dust under a specified, time-dependent physical description. This allows both the post-processing of hydrodynamical simulations and the usage of physical parametrizations, ranging in context from extra-galactic to protoplanetary disk scales. The framework consists of a core routine that solves gas-grain chemical reaction networks as a function of time, self-consistently coupled to either a user-defined or parametrized physical evolution of density, temperature and other physical input parameters. The chemistry is solved with a rate-equation formalism, and includes a three phase description, namely gas phase, ice surface and bulk ice. This includes transport between the gas and ice phases via freeze-out, thermal and non-thermal desorption mechanisms, as well as a geometrical treatment of the growth and shrinkage of the surface and bulk chemistry. The framework includes parametrizations for astrochemical modelling of cloud collapses, protostellar cores and shocks as well as the ability to provide user-defined inputs. This release of the framework focuses on many quality-of-life-improvements, including an object-oriented Python interface, an upgrade from two phase to three phases and expanded support for post-processing of hydrodynamical simulations and user-defined parametrizations. This manuscript provides an overview of the physics and chemistry included in UCLCHEM, as well as the inner workings of the solver routine and the programming interface.
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BibTeX
@misc{vermarien2026uclchem,
title = {{UCLCHEM 4.0: An open source gas-grain astrochemistry simulation framework}},
author = {Gijs Vermariën and Serena Viti and Tobias M. Dijkhuis and Le Ngoc Tram and Marcus Keil and Katarzyna M. Dutkowska and Felix D. Priestley},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.20265},
eprint = {2606.20265},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.20265},
}
RIS
TY - UNPB
TI - UCLCHEM 4.0: An open source gas-grain astrochemistry simulation framework
AU - Gijs Vermariën
AU - Serena Viti
AU - Tobias M. Dijkhuis
AU - Le Ngoc Tram
AU - Marcus Keil
AU - Katarzyna M. Dutkowska
AU - Felix D. Priestley
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2606.20265
UR - https://arxiv.org/abs/2606.20265
AB - Astrochemical modelling is a key tool for interpreting the formation and destruction of molecules in the interstellar medium, complementing the increasingly detailed observations enabled by modern day observational facilities. UCLCHEM is a comprehensive gas-grain astrochemical modelling framework that can compute the chemical evolution inside a parcel of gas and dust under a specified, time-dependent physical description. This allows both the post-processing of hydrodynamical simulations and the usage of physical parametrizations, ranging in context from extra-galactic to protoplanetary disk scales. The framework consists of a core routine that solves gas-grain chemical reaction networks as a function of time, self-consistently coupled to either a user-defined or parametrized physical evolution of density, temperature and other physical input parameters. The chemistry is solved with a rate-equation formalism, and includes a three phase description, namely gas phase, ice surface and bulk ice. This includes transport between the gas and ice phases via freeze-out, thermal and non-thermal desorption mechanisms, as well as a geometrical treatment of the growth and shrinkage of the surface and bulk chemistry. The framework includes parametrizations for astrochemical modelling of cloud collapses, protostellar cores and shocks as well as the ability to provide user-defined inputs. This release of the framework focuses on many quality-of-life-improvements, including an object-oriented Python interface, an upgrade from two phase to three phases and expanded support for post-processing of hydrodynamical simulations and user-defined parametrizations. This manuscript provides an overview of the physics and chemistry included in UCLCHEM, as well as the inner workings of the solver routine and the programming interface.
ER -