Diatomic-py: A Python module for calculating the rotational and hyperfine structure of 1Σ molecules

Abstract

We present a computer program to calculate the quantised rotational and hyperfine energy levels of Σ1 diatomic molecules in the presence of dc electric, dc magnetic, and off-resonant optical fields. Our program is applicable to the bialkali molecules used in ongoing state-of-the-art experiments with ultracold molecular gases. We include functions for the calculation of space-fixed electric dipole moments, magnetic moments and transition dipole moments. Program summaryProgram Title: Diatomic-PyCPC Library link to program files:https://doi.org/10.17632/3yfxnh5bn5.1Developer's repository link:https://doi.org/10.5281/zenodo.6632148Licensing provisions: BSD 3-clauseProgramming language: Python ≥ 3.7Nature of problem: Calculation of the rotational and hyperfine structure of Σ1 molecules in the presence of dc magnetic, dc electric, and off-resonant laser fields.Solution method: A matrix representation of the Hamiltonian is constructed in the uncoupled basis set. Eigenstates and eigenenergies are calculated by numerical diagonalization of the Hamiltonian.Additional comments including restrictions and unusual features: Restricted to calculating the Stark and Zeeman shifts with co-axial electric and magnetic fields.