DiPolMol-Py: A Python package for calculations for 2Σ ground-state molecules

We present the python package DiPolMol-Py, which can be used to calculate the rotational and hyperfine structure of Σ 2 molecules. The calculations can be performed in the presence of dc magnetic fields, dc electric fields and far off-resonant optical fields. We additionally include functions to calculate the polarisability of the molecule and the transition dipole moment between different energy eigenstates. The package is applicable to many of the molecules which can be laser cooled, specifically the alkaline earth fluorides. We provide a constants file which includes many of the required literature values for 40 CaF, 88 SrF and 138 BaF. Additional species can easily be added by updating this file. Program Title: DiPolMol-Py CPC Library link to program files: https://doi.org/10.17632/36gp2kd4jj.1 Developer's repository link: https://github.com/durham-qlm/DiPolMol Licensing provisions: BSD 3-clause Programming language: Python ≥3.11 Nature of problem: Calculating the rotational and hyperfine structure for Σ 2 ground state molecules both field free and in the presence of dc magnetic, electric and off-resonant light fields. Solution method: A Python package which calculates the eigenenergies and eigenvalues via diagonalization of the Hamiltonian. Additional comments including restrictions and unusual features: This package is based on previous work for Σ 1 molecules [1]. External magnetic and electric fields must be coaxial. [1] J.A. Blackmore, P.D. Gregory, J.M. Hutson, S.L. Cornish, Comput. Phys. Commun. 282 (2023) 108512, https://doi.org/10.1016/j.cpc.2022.108512 .