The global potential energy surface of PH2+(21A′) extrapolated to the complete basis set limit

It has been established that the proton transfer dynamics of P + ( P 3 ) + H 2 ( X 1 Σ g + ) → P H + ( A 2 Δ ) + H ( S 2 ) play an important role in determining the chain reaction of phosphorus-containing P H n + ( n = 0 − 4 ) compounds in the planetary ionosphere. This work presents an accurate global potential energy surface (PES) of P H 2 + ( 2 1 A ′ ) for the first time by fitting extensive ab initio energies from the aug-cc-pV(T, Q)Z level of theory using the multi-reference configuration interaction method including Davidson correction, and extrapolating the points to the complete basis set limit. The spectral parameters of PH + ( A 2 Δ) and H 2 ( X 1 Σ g + ) are shown to be in agreement with the data available in previous literature. Meanwhile, a detailed study of the topographical features of the global PES could be used as a reliable photolytic kinetic theory for the P + ( P 3 ) + H 2 ( X 1 Σ g + ) reaction. Furthermore, to demonstrate the validity of the new PES, we have explicitly taken into account the P + ( P 3 ) + H 2 ( X 1 Σ g + ) ( v = 0 , j = 0 ) → P H + ( A 2 Δ ) + H ( S 2 ) reaction, and assessed its feasibility in terms of reaction dynamics by calculating the integral cross-section via the time-dependent wave packet and quasi-classical trajectory approaches. The consequent results indicate that the new PES is suitable for thermochemical reactions.