A new accurate potential energy surface for HeTiO system and rotational quenching of TiO due to He collisions

Abstract A new accurate ab initio potential energy surface (PES) of the HeTiO system is constructed. The multi-reference configuration interaction with the Davidson correction is used to obtain the energy points, and the neural network method is employed to fit the PES. State-to-state rotational quenching cross sections and rate coefficients are obtained over a wide range based on the PES. Wigner threshold law is proved to be valid in the ultralow energy regime. In comparison with 3 He, 4 He is more efficient for the TiO molecule cooling process in the dominant transition j  = 1 → 0 due to the isotope effect.