ExoMol line lists XXXI: C_2_

These line lists cover rovibronic transitions between the eight lowest electronic states: X, A, B, B', a, b, c, d. Potential energy curves (PECs) and transition dipole moment curves are computed on a large grid of geometries using the aug-cc-pwCVQZ-DK/MRCI level of theory including core and core-valence correlations and scalar relativistic energy corrections.

The same level of theory is used to compute spin-orbit and electronic angular momentum couplings. The PECs and couplings are refined by fitting to the empirical (MARVEL) energies of C_2_ using the nuclear-motion program Duo. The transition dipole moment curves are represented as analytical functions to reduce the numerical noise when computing transition line strengths.