Hyperfine excitation of NS + due to para-H 2 (j = 0) impact

Sulfur bearing nitrogenous compounds have been observed in space over this last decade. Modeling their abundances has been done using rate coefficients of isoelectronic molecules. In order to satisfy the astrophysical precision required, we report the actual rate coefficients of NS + induced by collision with the most abundant interstellar species (para-H 2). Considering the 23 low-lying rotational levels of NS + , we were able to compute the (hyperfine) rate coefficients up to 100 K. These latter were carried out by averaging cross sections over the Maxwell-Boltzmann velocity distribution. The state-to-state inelastic cross sections were determined in the quantum mechanical close coupling approach for total energies ranging up to 1,400 cm −1. These dynamic data result from a four dimensional potential energy surface (4D-PES) which was spherically averaged over the H 2 orientations. The 4D-PES was calculated using the the explicitly correlated coupled cluster method with simple, double and non-iterative triple excitation (CCSD(T)-F12) connected to the augmented-correlation consistent-polarized valence triple zeta Gaussian basis set (aug-cc-pVTZ). The so-averaged PES presents a very deep well of 596.72 cm −1 at R = 5.94 a 0 and θ 1 = 123.20 •. Discussions on the propensity rules for the (hyperfine) rate coefficients were made and they are in favor of (∆ j = ∆F) ∆ j = 1 transitions. The results presented here may be crucially needed in order to accurately model the NS + abundance in space. In addition, we expect that this paper will encourage investigations on the sulfur bearing nitrogenous compounds.