An accurate NH(XA'') CHIPR potential energy surface extrapolation to the complete basis set limit and dynamics of the N(D) + H(X+g) reaction.

The amidogen radical (NH) and its associated N(D) + H(XΣ+g) → H(S) + NH(XΣ) reaction have great significance in interstellar chemistry and the accurate potential energy surface (PES) is the basis for studying them. We report a new and accurate PES for the ground state NH(XA'') using the combined-hyperbolic-inverse-power-representation methodology based on 7970 energy points computed at the Davidson-corrected internally contracted multireference configuration interaction level of theory. Both aug-cc-pVTZ and aug-cc-pVQZ basis sets have been employed to extrapolate the energies to the complete basis set limit. The analytical PES reproduces well with the energy points with a root mean square deviation of 55.7 cm. The topographical features of the analytical PES are examined in detail and agree well with the previous theoretical results. The integral cross sections and rate constants of the N(D) + H(XΣ+g) → H(S) + NH(XΣ) reaction are obtained using the quasi-classical trajectory method and the time-dependent wave packet method and then compared with the available theoretical and experimental values.