Empirical Potential Energy Curve for the Ground State of CaH from a Multiisotopologue Direct Potential Fit Analysis

Vibration-rotation and pure rotational data in the X2Σ+ ground state and electronic data from the A2Π – X2Σ+ and B2Σ+ − X2Σ+ transitions of CaH and CaD were used in the quantum-mechanical direct-potential-fit (DPF) analysis to determine an analytic potential energy function for the X2Σ+ ground state of CaH, and a radial correction function for the CaD isotopologue. The potential energy function for the X2Σ+ state reproduces all the observed energy levels of CaH and CaD within their experimental uncertainties. In addition, it follows the ab initio potential very closely outside the data region, and has the theoretical long-range behavior near the asymptote.