Accurate ab initio based global adiabatic potential energy surfaces for the 13A′′, 13A′ and 21A′ states of SiH2

Three accurate global adiabatic potential energy surfaces for the 1(3)A '', 1(3)A' and 2(1)A' states of SiH2 are constructed by fitting numerous ab initio energies calculated at the aug-cc-pV(Q+d)Z and aug-cc-pV(5+d)Z basis sets based on the multi-reference configuration interaction level with Davidson correction. It is worth noting that the potential energy surface of the 1(3)A '' state is established for the first time. The topographic features of these novel potential energy surfaces are investigated in detail and are very consistent with those obtained in the available literature. Moreover, the integral cross-sections of the corresponding reaction are calculated for the first time using a quasi-classical trajectory method and time-dependent wave packet method, indicating that the 1(3)A '' state makes a major contribution to the reaction of Si(P-3) + H-2(X-1 sigma+(g)) (v = 0, j = 0) -> H(S-2) + SiH(X-2 pi) at high collision energies. These new potential energy surfaces provide a reliable foundation for investigation of the dynamics and a component for constructing larger silicon-/hydrogen-containing systems.