Interpolated potential energy surface and dynamics for the reactions between N(4S) and H3+(1A1′)

An ab initio potential energy surface for the quartet electronic state of ${\mathrm{NH}}_{\mathrm{3}}^{\mathrm{+}}$ has been constructed at the $\mathrm{MP2/6-31G}\mathrm{(d,p)}$ level of theory. The accuracy of this surface has been verified by comparison with high levels of theory. Classical simulations of the collision of $\mathrm{N}{(}^4\mathrm{S)}$ and ${\mathrm{H}}_{\mathrm{3}}^{\mathrm{+}}{(}^1{A}_1^{\prime })$ showed no reaction to form ${\mathrm{NH}}_{\mathrm{2}}^{\mathrm{+}}\mathrm{+H}$ at thermal energies. The possibility of reaction via surface hopping to the doublet electronic state has been investigated by calculation of the quartet–doublet energy gap at the $\mathrm{MRCI/6-311+G}\text{(2df,p)}$ level of theory. No evidence of surface crossing could be found for configurations accessible at thermal energies.