Sodium hydride NaH( X 1 Σ + ) in collision with helium He( 1 S ) at low temperature: Potential energy surface and rotational rate coefficients

The ro-vibrational transitions of NaH are crucially needed for the control of photo-association processes resulting from its formation and for accurately modeling the NaH abundance in space. In this work, we constructed new PESs of the NaH-He system. The potentials were computed at the CCSD(T)-F12/ cc-pVTZ level of theory. Each of the PESs presents two local minima. From these PESs, we calculated rotational cross sections of NaH induced by collision with He using the close coupling approach. These cross sections were then averaged at low temperature to obtain the collisional rates. The propensity rules favorite odd $\Delta j$ transitions. The collisional rates presented in this paper may be crucial for the astrophysical community. The three dimensional PES can be used later to compute ro-vibrational quenching rate coefficients to interpret the NaH collisional interaction with laser-cooled atoms.