Diabatic Potential Energy Surfaces of the <scp> CH ₂ </scp> ( <scp> ¹ A″ </scp> ) System and Dynamics Studies of the C( <scp> ¹ D </scp> ) +  <scp> H ₂ </scp> Reaction

ABSTRACT The global diabatic potential energy surfaces (PESs) of the CH 2 ( 1 A″) system were constructed using the neural network method with symmetry‐constrained function based on 15 726 ab initio points. To achieve high accuracy, the MRCI‐F12 method and aug‐cc‐pVTZ basis set for C and H atoms were adopted in the ab initio calculations. The newly constructed diabatic PESs were examined in detail by comparison with the ab initio points. Furthermore, the topographic features of the diabatic PESs were described which indicate that the diabatic PESs present the non‐adiabatic transition processes reasonably between the electronic states. In addition, both adiabatic and non‐adiabatic dynamics calculations of the C( 1 D) + H 2 → CH(X 2 Π) + H reaction were carried out using the time‐dependent wave packet method. By comparing the adiabatic and non‐adiabatic results, it was found that non‐adiabatic effects play an important role in the reaction process, especially in the high collision energy region, where the adiabatic results underestimate the actual values.