Globally Accurate Gaussian Process Potential Energy Surface and Quantum Dynamics Studies on the Li(2S) + Na2 → LiNa + Na Reaction at Low Collision Energies

Abstract

The LiNa2 reactive system has recently received great attention in the experimental study of ultracold chemical reactions, but the corresponding theoretical calculations have not been carried out. Here, we report the first globally accurate ground-state LiNa2 potential energy surface (PES) using a Gaussian process model based on only 1776 actively selected high-level ab initio training points. The constructed PES had high precision and strong generalization capability. On the new PES, the quantum dynamics calculations on the Li(2S) + Na2(v = 0, j = 0) → LiNa + Na reaction were carried out in the 0.001–0.01 eV collision energy range using an improved time-dependent wave packet method. The calculated results indicate that this reaction is dominated by a complex-forming mechanism at low collision energies. The presented dynamics data provide guidance for experimental research, and the newly constructed PES could be further used for ultracold reaction dynamics calculations on this reactive system.

Quantum Dynamics Studies of the Li + Na2 (V = 0, j = 0) → Na + NaLi Reaction on a New Neural Network Potential Energy Surface

“…(a) Total DCSs of the Li + Na 2 ( v = 0, j = 0) → Na + NaLi reaction as functions of product scattering angle and collision energy. (b) Total DCSs as a function of product scattering angle at two selected collision energies and compared with the results of ref . (Dash lines).…”

“…The Na 2 Li reaction system, with its fewer electron numbers and lighter atomic mass compared to most alkali metal reaction systems, enables more precise results in PES and dynamics calculations. The ground electronic state PES of the Na 2 Li reaction system, referred to as YCBC 55 PES, was constructed using the Gaussian process method in recent studies. Subsequently, the dynamics of the Li + Na 2 → Na + NaLi reaction were investigated within a collision energy range of 0.001−0.01 eV.…”

State-to-State Quantum Dynamics Study of Intramolecular Isotope Effects on Be(1S) + HD (v0 = 2, j0 = 0) → BeH/BeD + H/D Reaction

“…The most reliable strategy for studying reaction dynamics theoretically is to perform quantum mechanics calculations on a high-quality PES [ 38 , 39 , 40 ]. The quantum TDWP method [ 41 , 42 , 43 , 44 , 45 ] can not only accurately calculate dynamics data but also has a relatively small numerical cost, meaning that it has been widely applied to simple reaction systems [ 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ]. A detailed description of the TDWP method has been presented in the relevant literature, and we only give the essentials and main equations.…”

Neural network Gaussian processes as efficient models of potential energy surfaces for polyatomic molecules

“…Multiple previous articles have modelled PES by GPs [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. A GP can be viewed as an infinite-…”

“…A major thrust of recent research has been to explore applications of machine learning (ML) methods for building accurate and data-efficient models of PES. ML models of PES demonstrated in the literature are either artificial neural networks (NNs) [1][2][3][4][5][6][7][8][9][10][11][12][13][14] or kernel models , most often in the form of kernel ridge regression (KRR) [15][16][17][18][19][20] or Gaussian process (GP) regression [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. Generally, the accuracy of a ML model of PES can be improved by: (i) increasing the number n of potential energy points used for training the model; (ii) optimizing the complexity of the model.…”