A new potential energy surface for the ground electronic state of the LiH₂ system, and dynamics studies on the H(²S) + LiH(X¹Σ⁺) → Li(²S) + H₂(X¹Σ_g⁺) reaction

Abstract

A new global potential energy surface (PES) is obtained for the ground electronic state of the LiH2 system based on high-level energies. The energy points are calculated at the multireference configuration interaction level with aug-cc-pVXZ (X = Q, 5) basis sets, and these energies are extrapolated to the complete basis set limit. The neural network method and hierarchical construction scheme are applied in the fitting process and the root mean square error of the fitting result is very small (0.004 eV). The dissociation energies and equilibrium distances for LiH(X(1)Σ(+)) and H2(X(1)Σg(+)) obtained from the new PES are in good agreement with the experimental data. On the new PES, time-dependent wave packet studies for the H((2)S) + LiH(X(1)Σ(+)) → Li((2)S) + H2(X(1)Σg(+)) reaction have been carried out. In this reaction, no threshold is found due to the absence of an energy barrier on the minimum energy path. The calculated integral cross sections are high at low collision energy and will decrease with the increase of the collision energy. The product molecule H2 tends to be forward scattering due to direct reactive collisions, which becomes more evident at higher collision energies.

New global potential energy surface of the MgH2 system and dynamics studies of the reaction H + MgH → Mg + H2

“…The permutation invariant polynomial neural network (PIP‐NN) method is used to fit the PES; PIP‐NN is widely used in PES construction, and has been used for reactions such as H + LiH, and O + + H 2 . First, we transform the bond length to Q 1 = 1/ r 1 , Q 2 = 1/ r 2 + 1/ r 3 , and Q 3 = 1/( r 1 * r 3 ), where r 1 is the bond length of the H 2 molecule, and r 2 and r 3 are correspond to the two MgH bond lengths.…”

Global diabatic potential energy surfaces and quantum dynamical studies for the Li(2p) + H2(X1Σ+g) → LiH(X1Σ+) + H reaction

“…The TDWP method is a powerful tool to calculate initial state selected reactive collision and has been applied widely in many reactions144647484950. A brief introduction of TDWP method which used here is given in this work and the detailed discussions can be found in relevant literature4849.…”

“…This PES shows an unphysical well at the Li(2s) + H 2 (X 1 Σ + g ) asymptotic valley. In 2009, two PESs of the ground states of LiH 2 system were reported by Prudente et al and Wernli et al 1213 Recently, Chen and co-workers presented a high-precision PES for the ground state of the LiH 2 system14. All the four PESs were employed to study the reaction dynamics of the LiH(X 1 Σ + ) + H → Li(2s) + H 2 (X 1 Σ + g ) reaction using the quasi-classical trajectory (QCT) and time-dependent wave packet (TDWP) method12151617.…”

A new potential energy surface for the H2S system and dynamics study on the S(1D) + H2(X1Σg+) reaction

“…The TDWP method is a powerful tool with which to study reaction dynamics and has been applied in our previous studies373839. In this paper, the TDWP method is introduced in brief, and more details can be found in the relevant literature4041.…”