Bayesian Analysis of Theoretical Rotational Constants From Low-Cost Electronic Structure Methods

With ever increasing usage of electronic structure programs by the microwave spectroscopy community, there is a growing need to assess the performance of commonly used, low-cost quantum chemical methods, particularly with respect to rotational constants because these quantities are central in guiding experiments. Here, we systematically benchmark the predictive power afforded by several low-level ab initio methods and density functionals combined with a variety of basis sets that are commonly employed in the rotational spectroscopy literature. The data set in our analysis consists of 6,916 optimized geometries of 76 representative species where high resolution experimental gas-phase rotational constants are available. We adopted a Bayesian approach for analyzing the performance of each method and basis set combination, employing Hamiltonian Monte Carlo sampling to assess the uncertainty in theoretical predictions of rotational constants and dipole moments. Furthermore, scaling factors that can be used to ...