Electronic structure, spectroscopic constants, and transition properties of NaC 0/+1/−1 diatomic species: An ab initio investigation

Diatomic species play a pivotal role in complex media, such as the interstellar and circumstellar media. Furthermore, there is a notable lack of information regarding NaC and its ions, NaC${}^{+}$ and NaC${}^{-}$, despite the pervasiveness of the carbon element (C) and the validated role of Na-bearing molecules as organic reagents or in catalytic processes. In this study, ab initio multi-reference calculations, including core valence and complete basis set schemes, were employed to accurately determine the potential energy curves (PECs), dipole moment functions (DMFs) and transition dipole moments (TDMs) of ten, three and ten low-lying electronic states energies, respectively, for NaC, NaC${}^{+}$ and NaC${}^{-}$ diatomics species. The obtained results permitted the accurate determination of spectroscopic constants and vibrational transition properties, including vibrational level energies, Franck–Condon factors (FCFs), Einstein coefficients, absorption band oscillator strengths, vibrational transition energies and radiative lifetimes of allowed transitions. The predicted adiabatic ionisation energy value for NaC is 6.659 eV, while the vertical ionisation energy value is 6.676 eV. Similarly, the predicted adiabatic electron affinity value for NaC is 0.614 eV, while the vertical electron affinity value is 0.613 eV.