Theoretical research on the geometric structure and electronic properties of medium-sized LaHnq (n=2–20, q=0, 1) clusters

Abstract

In cluster scientific research, determining the ground state structure is a fundamental aspect of investigating the properties and applications of clusters. However, the determination of the lowest-energy structure of clusters is not only a complex global optimization problem but also a crucial challenge in current cluster research. In the work the geometric structure and electronic properties of LaHn0/+ (n = 2–20) nanoclusters with potential for hydrogen storage are investigated using Crystal structure AnaLYsis by Particle Swarm Optimization (CALYPSO) method and Density Functional Theory (DFT). By calculating the average adsorption energy and hydrogen storage mass fraction, it is predicted that neutral LaH13 and cationic LaH14+ clusters exhibit high hydrogen storage densities of 8.6 wt% and 9.2 wt%, respectively. Furthermore, the molecular orbital composition and internal chemical bond binding mode were analyzed using adaptive natural density partition (AdNDP) and natural bond orbital (NBO). The results indicate that the strong hybridization between La 5d orbitals and H 1s orbitals is the primary factor contributing to the high stability of both neutral LaH13 and cationic LaH14+ clusters.