Numerical modeling of laser cooling in molecules: From simple diatomics to polyatomics and radioactive species

Felix Kogel; Tatsam Garg; Phillip Groß; Lukas Leczek; Marian Rockenhäuser; Neil Shah; Jakob Weiß; Andreas Schindewolf; Tim Langen

doi:10.1016/j.cpc.2026.110235

arXiv · 2510.16203

Numerical modeling of laser cooling in molecules: From simple diatomics to polyatomics and radioactive species

Felix Kogel·Tatsam Garg·Phillip Groß·Lukas Leczek·Marian Rockenhäuser·Neil Shah·Jakob Weiß·Andreas Schindewolf·Tim Langen

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Abstract

Optical Bloch equations and rate equations serve as powerful tools to model light-matter interactions from textbook-like two-level atoms to the complex internal dynamics of molecules. A particular challenge in this context is posed by molecular laser cooling, where many dozens or hundreds of levels need to be taken into account for a comprehensive modeling. Here, we present MoleCool, a numerically efficient Python toolbox to implement and solve the corresponding differential equation systems. We illustrate both the capabilities of the toolbox and some of the intricacies of molecular laser cooling by educational examples, which range from simple Rabi oscillations to spontaneous and coherent cooling schemes for various currently studied or considered molecular species. This includes, in particular, a comprehensive modeling of laser cooling dynamics with full hyperfine structure resolution in radioactive radium monofluoride (RaF), as well as studies of other complex species such as barium monofluoride (BaF) and ytterbium monohydroxide (YbOH).

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Felix Kogel, Tatsam Garg, Phillip Groß, Lukas Leczek, Marian Rockenhäuser, Neil Shah, Jakob Weiß, Andreas Schindewolf, Tim Langen. 2025-10-17. Numerical modeling of laser cooling in molecules: From simple diatomics to polyatomics and radioactive species. https://doi.org/10.1016/j.cpc.2026.110235

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