New Diabatic Potential Energy Surfaces for the Li + H 2 Reaction and Time-Dependent Quantum Wave Packet Studies.

New global diabatic potential energy surfaces (DPESs) for the ground (1 2 A ') and first excited (2 2 A ') states for the Li + H 2 system were developed, with more than 30,000 energy points at the IC-MRCI+Q level of theory, utilizing the aug-cc-pV5Z basis set for the H atoms and the cc-pCV5Z basis set for the Li atom, fitted by a single neural network (NN) with symmetry. Product state-resolved quantum dynamics calculations of the nonadiabatic reaction Li ( 2 P ) + H 2 ( X 1 ∑ g + , v 0 = 0, j 0 = 0) → LiH ( X 1 ∑ + ) + H( 2 S ) were carried out using these new DPESs and also the previous HYLC-DPESs. The numerical results suggested that our newly constructed DPESs provided an accurate description of the LiH 2 system.