Theoretical study of the lowest electronic states of CaH and CaH+ molecules

The 15 lowest states of CaH and the 14 lowest states of CaH+ have been calculated using a non-empirical effective core potential for the Ne-like core electrons of Ca. Full valence configuration interaction calculations were followed by the inclusion of intershell effects via a recently proposed core polarization potential. This approach has been shown to correctly reproduce the experimental spectra of both neutral and ionized calcium atom and in the present work its efficiency is assessed by comparisons with other theoretical and experimental results. For instance, the remaining small discrepancy noted between the calculated (Re=3.744 au, De=1.66 eV, Ïe=1263 cm−1) and experimental results for the ground state (Re=3.78 au, De ≈ 1.70 eV, Ïe=1298 cm−1) is attributed to core-core correlation effects.